diff --git a/features.txt b/features.txt
index 6004cca4bf..d911d88a4d 100644
--- a/features.txt
+++ b/features.txt
@@ -77,6 +77,10 @@ regexp-v-flag
 # https://github.com/tc39/proposal-decorators
 decorators
 
+# Decorator Metadata
+# https://github.com/tc39/proposal-decorator-metadata
+decorator-metadata
+
 # Duplicate named capturing groups
 # https://github.com/tc39/proposal-duplicate-named-capturing-groups
 regexp-duplicate-named-groups
diff --git a/test/built-ins/Function/prototype/Symbol.metadata.js b/test/built-ins/Function/prototype/Symbol.metadata.js
new file mode 100644
index 0000000000..f604ae19b4
--- /dev/null
+++ b/test/built-ins/Function/prototype/Symbol.metadata.js
@@ -0,0 +1,19 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-function.prototype-@@metadata
+description: Function.prototype[Symbol.metadata] property descriptor
+info: |
+    The initial value of the @@metadata property is null.
+    This property has the attributes { [[Writable]]: false, [[Enumerable]]:
+    false, [[Configurable]]: false }.
+includes: [propertyHelper.js]
+features: [decorator-metadata]
+---*/
+
+verifyProperty(Function.prototype, Symbol.metadata, {
+    value: null,
+    writable: false,
+    enumerable: false,
+    configurable: false
+});
diff --git a/test/built-ins/Symbol/metadata/cross-realm.js b/test/built-ins/Symbol/metadata/cross-realm.js
new file mode 100644
index 0000000000..59e4c0dded
--- /dev/null
+++ b/test/built-ins/Symbol/metadata/cross-realm.js
@@ -0,0 +1,14 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-symbol.metadata
+description: Value shared by all realms
+info: |
+  Unless otherwise specified, well-known symbols values are shared by all
+  realms.
+features: [cross-realm, decorator-metadata]
+---*/
+
+var OSymbol = $262.createRealm().global.Symbol;
+
+assert.sameValue(Symbol.metadata, OSymbol.metadata);
diff --git a/test/built-ins/Symbol/metadata/prop-desc.js b/test/built-ins/Symbol/metadata/prop-desc.js
new file mode 100644
index 0000000000..897f9a9ecd
--- /dev/null
+++ b/test/built-ins/Symbol/metadata/prop-desc.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-symbol.metadata
+description: >
+    `Symbol.metadata` property descriptor
+info: |
+    This property has the attributes { [[Writable]]: false, [[Enumerable]]:
+    false, [[Configurable]]: false }.
+includes: [propertyHelper.js]
+features: [decorator-metadata]
+---*/
+
+assert.sameValue(typeof Symbol.metadata, 'symbol');
+verifyNotEnumerable(Symbol, 'metadata');
+verifyNotWritable(Symbol, 'metadata');
+verifyNotConfigurable(Symbol, 'metadata');
diff --git a/test/language/expressions/class/decorator/metadata/context-metadata-prop-desc.js b/test/language/expressions/class/decorator/metadata/context-metadata-prop-desc.js
new file mode 100644
index 0000000000..44278f0152
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/context-metadata-prop-desc.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-createdecoratorcontextobject
+description: >
+    Property descriptor for metadata property of decorator context object.
+info: |
+    CreateDecoratorContextObject ( kind, name, initializers, decorationState, metadataObj [ , isStatic ] )
+    [...]
+    13. Perform ! CreateDataPropertyOrThrow(contextObj, "metadata", metadata).
+    14. Return contextObj.
+includes: [propertyHelper.js]
+features: [decorators, decorator-metadata]
+---*/
+
+var contextObj;
+function dec(_, context) {
+  contextObj = context;
+}
+
+void @dec class C {};
+assert.sameValue(typeof contextObj.metadata, "object");
+verifyNotEnumerable(contextObj, "metadata");
+verifyWritable(contextObj, "metadata");
+verifyConfigurable(contextObj, "metadata");
diff --git a/test/language/expressions/class/decorator/metadata/context-metadata.js b/test/language/expressions/class/decorator/metadata/context-metadata.js
new file mode 100644
index 0000000000..12146481d3
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/context-metadata.js
@@ -0,0 +1,59 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-createdecoratorcontextobject
+description: >
+    Property descriptor for metadata property of decorator context object.
+info: |
+    CreateDecoratorContextObject ( kind, name, initializers, decorationState, metadataObj [ , isStatic ] )
+    [...]
+    13. Perform ! CreateDataPropertyOrThrow(contextObj, "metadata", metadata).
+    14. Return contextObj.
+includes: [deepEqual.js]
+features: [decorators, decorator-metadata]
+---*/
+
+var kinds = {
+    "class": false,
+    "public method": false,
+    "public getter": false,
+    "public setter": false,
+    "public field": false,
+    "public accessor": false,
+    "private method": false,
+    "private getter": false,
+    "private setter": false,
+    "private field": false,
+    "private accessor": false,
+};
+function dec(_, context) {
+    const key = `${context.private ? "private" : "public"} ${context.kind}`;
+    kinds[key] = typeof context.metadata === "object";
+}
+
+void @dec class C {
+    @dec method() {}
+    @dec get getter() {}
+    @dec set setter(x) {}
+    @dec field;
+    @dec accessor accessor;
+    @dec #method() {}
+    @dec get #getter() {}
+    @dec set #setter(x) {}
+    @dec #field;
+    @dec accessor #accessor;
+};
+
+assert.deepEqual(kinds, {
+    "class": true,
+    "public method": true,
+    "public getter": true,
+    "public setter": true,
+    "public field": true,
+    "public accessor": true,
+    "private method": true,
+    "private getter": true,
+    "private setter": true,
+    "private field": true,
+    "private accessor": true,
+});
diff --git a/test/language/expressions/class/decorator/metadata/metadata-attached-when-class-is-decorated.js b/test/language/expressions/class/decorator/metadata/metadata-attached-when-class-is-decorated.js
new file mode 100644
index 0000000000..558ea5c6f4
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/metadata-attached-when-class-is-decorated.js
@@ -0,0 +1,43 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    Metadata is only attached when a class or class element is decorated.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+let C1 = @dec class C1 {};
+assert.sameValue(typeof C1[Symbol.metadata], "object");
+
+let C2 = class C2 { @dec method() {} };
+assert.sameValue(typeof C2[Symbol.metadata], "object");
+
+let C3 = class C3 {};
+assert.sameValue(typeof C3[Symbol.metadata], "undefined");
diff --git a/test/language/expressions/class/decorator/metadata/metadata-inheritance-not-affected-by-setPrototype-on-class.js b/test/language/expressions/class/decorator/metadata/metadata-inheritance-not-affected-by-setPrototype-on-class.js
new file mode 100644
index 0000000000..4d133108e8
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/metadata-inheritance-not-affected-by-setPrototype-on-class.js
@@ -0,0 +1,45 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    Metadata on a derived class inherits from the metadata of the declared super class.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+class UndecoratedBase {}
+
+let Base = @dec class Base {};
+const baseMetadata = Base[Symbol.metadata];
+
+let Derived = @dec class Derived extends Base { };
+Object.setPrototypeOf(Derived, UndecoratedBase);
+
+const derivedMetadata = Derived[Symbol.metadata];
+assert.sameValue(Object.getPrototypeOf(derivedMetadata), baseMetadata);
diff --git a/test/language/expressions/class/decorator/metadata/metadata-inheritance-not-affected-when-base-metadata-replaced.js b/test/language/expressions/class/decorator/metadata/metadata-inheritance-not-affected-when-base-metadata-replaced.js
new file mode 100644
index 0000000000..458bd0d65c
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/metadata-inheritance-not-affected-when-base-metadata-replaced.js
@@ -0,0 +1,45 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    Metadata on a derived class inherits from the metadata of the declared super class.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+class UndecoratedBase {}
+
+let Base = @dec class Base {};
+const baseMetadata = Base[Symbol.metadata];
+
+let Derived = @dec class Derived extends Base { };
+Base[Symbol.metadata] = {};
+
+const derivedMetadata = Derived[Symbol.metadata];
+assert.sameValue(Object.getPrototypeOf(derivedMetadata), baseMetadata);
diff --git a/test/language/expressions/class/decorator/metadata/metadata-inheritance.js b/test/language/expressions/class/decorator/metadata/metadata-inheritance.js
new file mode 100644
index 0000000000..3af3b9fd88
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/metadata-inheritance.js
@@ -0,0 +1,42 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    Metadata is only attached when a class or class element is decorated.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+let Base = @dec class Base {};
+const baseMetadata = Base[Symbol.metadata];
+assert.sameValue(Object.getPrototypeOf(baseMetadata), null);
+
+let Derived = @dec class Derived extends Base { };
+const derivedMetadata = Derived[Symbol.metadata];
+assert.sameValue(Object.getPrototypeOf(derivedMetadata), baseMetadata);
diff --git a/test/language/expressions/class/decorator/metadata/metadata-is-plain-object.js b/test/language/expressions/class/decorator/metadata/metadata-is-plain-object.js
new file mode 100644
index 0000000000..ba795e7266
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/metadata-is-plain-object.js
@@ -0,0 +1,32 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    The metadata object is a regular, extensible JS object.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+let C = @dec class C {};
+const metadata = C[Symbol.metadata];
+assert(Object.isExtensible(metadata));
diff --git a/test/language/expressions/class/decorator/metadata/metadata-is-same-as-context-metadata.js b/test/language/expressions/class/decorator/metadata/metadata-is-same-as-context-metadata.js
new file mode 100644
index 0000000000..53fce57f72
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/metadata-is-same-as-context-metadata.js
@@ -0,0 +1,47 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    The metadata object provided to a decorator is the same one installed on the class.
+info: |
+    CreateDecoratorContextObject ( kind, name, initializers, decorationState, metadataObj [ , isStatic ] )
+
+    [...]
+    13. Perform ! CreateDataPropertyOrThrow(contextObj, "metadata", metadata).
+    14. Return contextObj.
+
+    ClassDefinitionEvaluation
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+var contextObj;
+function dec(_, context) {
+  contextObj = context;
+}
+
+let C = @dec class C {};
+assert.sameValue(C[Symbol.metadata], contextObj.metadata);
diff --git a/test/language/expressions/class/decorator/metadata/metadata-prop-desc.js b/test/language/expressions/class/decorator/metadata/metadata-prop-desc.js
new file mode 100644
index 0000000000..41c95e0f1f
--- /dev/null
+++ b/test/language/expressions/class/decorator/metadata/metadata-prop-desc.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-createdecoratorcontextobject
+description: >
+    Property descriptor for metadata property of decorator context object.
+info: |
+    CreateDecoratorContextObject ( kind, name, initializers, decorationState, metadataObj [ , isStatic ] )
+    [...]
+    13. Perform ! CreateDataPropertyOrThrow(contextObj, "metadata", metadata).
+    14. Return contextObj.
+includes: [propertyHelper.js]
+features: [decorators, decorator-metadata]
+---*/
+
+var contextObj;
+function dec(_, context) {
+  contextObj = context;
+}
+
+let C = @dec class C {};
+assert.sameValue(typeof contextObj.metadata, "object");
+verifyNotEnumerable(contextObj, "metadata");
+verifyWritable(contextObj, "metadata");
+verifyConfigurable(contextObj, "metadata");
diff --git a/test/language/statements/class/decorator/metadata/context-metadata-prop-desc.js b/test/language/statements/class/decorator/metadata/context-metadata-prop-desc.js
new file mode 100644
index 0000000000..2113eceb0f
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/context-metadata-prop-desc.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-createdecoratorcontextobject
+description: >
+    Property descriptor for metadata property of decorator context object.
+info: |
+    CreateDecoratorContextObject ( kind, name, initializers, decorationState, metadataObj [ , isStatic ] )
+    [...]
+    13. Perform ! CreateDataPropertyOrThrow(contextObj, "metadata", metadata).
+    14. Return contextObj.
+includes: [propertyHelper.js]
+features: [decorators, decorator-metadata]
+---*/
+
+var contextObj;
+function dec(_, context) {
+  contextObj = context;
+}
+
+@dec class C {}
+assert.sameValue(typeof contextObj.metadata, "object");
+verifyNotEnumerable(contextObj, "metadata");
+verifyWritable(contextObj, "metadata");
+verifyConfigurable(contextObj, "metadata");
diff --git a/test/language/statements/class/decorator/metadata/context-metadata.js b/test/language/statements/class/decorator/metadata/context-metadata.js
new file mode 100644
index 0000000000..0ba7776556
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/context-metadata.js
@@ -0,0 +1,59 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-createdecoratorcontextobject
+description: >
+    Property descriptor for metadata property of decorator context object.
+info: |
+    CreateDecoratorContextObject ( kind, name, initializers, decorationState, metadataObj [ , isStatic ] )
+    [...]
+    13. Perform ! CreateDataPropertyOrThrow(contextObj, "metadata", metadata).
+    14. Return contextObj.
+includes: [deepEqual.js]
+features: [decorators, decorator-metadata]
+---*/
+
+var kinds = {
+    "class": false,
+    "public method": false,
+    "public getter": false,
+    "public setter": false,
+    "public field": false,
+    "public accessor": false,
+    "private method": false,
+    "private getter": false,
+    "private setter": false,
+    "private field": false,
+    "private accessor": false,
+};
+function dec(_, context) {
+    const key = `${context.private ? "private" : "public"} ${context.kind}`;
+    kinds[key] = typeof context.metadata === "object";
+}
+
+@dec class C {
+    @dec method() {}
+    @dec get getter() {}
+    @dec set setter(x) {}
+    @dec field;
+    @dec accessor accessor;
+    @dec #method() {}
+    @dec get #getter() {}
+    @dec set #setter(x) {}
+    @dec #field;
+    @dec accessor #accessor;
+}
+
+assert.deepEqual(kinds, {
+    "class": true,
+    "public method": true,
+    "public getter": true,
+    "public setter": true,
+    "public field": true,
+    "public accessor": true,
+    "private method": true,
+    "private getter": true,
+    "private setter": true,
+    "private field": true,
+    "private accessor": true,
+});
diff --git a/test/language/statements/class/decorator/metadata/metadata-attached-when-class-is-decorated.js b/test/language/statements/class/decorator/metadata/metadata-attached-when-class-is-decorated.js
new file mode 100644
index 0000000000..5136d41bf3
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/metadata-attached-when-class-is-decorated.js
@@ -0,0 +1,43 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    Metadata is only attached when a class or class element is decorated.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+@dec class C1 {}
+assert.sameValue(typeof C1[Symbol.metadata], "object");
+
+class C2 { @dec method() {} }
+assert.sameValue(typeof C2[Symbol.metadata], "object");
+
+class C3 {}
+assert.sameValue(typeof C3[Symbol.metadata], "undefined");
diff --git a/test/language/statements/class/decorator/metadata/metadata-inheritance-not-affected-by-setPrototype-on-class.js b/test/language/statements/class/decorator/metadata/metadata-inheritance-not-affected-by-setPrototype-on-class.js
new file mode 100644
index 0000000000..daf2793204
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/metadata-inheritance-not-affected-by-setPrototype-on-class.js
@@ -0,0 +1,45 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    Metadata on a derived class inherits from the metadata of the declared super class.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+class UndecoratedBase {}
+
+@dec class Base {}
+const baseMetadata = Base[Symbol.metadata];
+
+@dec class Derived extends Base { }
+Object.setPrototypeOf(Derived, UndecoratedBase);
+
+const derivedMetadata = Derived[Symbol.metadata];
+assert.sameValue(Object.getPrototypeOf(derivedMetadata), baseMetadata);
diff --git a/test/language/statements/class/decorator/metadata/metadata-inheritance-not-affected-when-base-metadata-replaced.js b/test/language/statements/class/decorator/metadata/metadata-inheritance-not-affected-when-base-metadata-replaced.js
new file mode 100644
index 0000000000..8a2a464c0a
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/metadata-inheritance-not-affected-when-base-metadata-replaced.js
@@ -0,0 +1,45 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    Metadata on a derived class inherits from the metadata of the declared super class.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+class UndecoratedBase {}
+
+@dec class Base {}
+const baseMetadata = Base[Symbol.metadata];
+
+@dec class Derived extends Base { }
+Base[Symbol.metadata] = {};
+
+const derivedMetadata = Derived[Symbol.metadata];
+assert.sameValue(Object.getPrototypeOf(derivedMetadata), baseMetadata);
diff --git a/test/language/statements/class/decorator/metadata/metadata-inheritance.js b/test/language/statements/class/decorator/metadata/metadata-inheritance.js
new file mode 100644
index 0000000000..8c1f2ec5f5
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/metadata-inheritance.js
@@ -0,0 +1,42 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    Metadata is only attached when a class or class element is decorated.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+@dec class Base {}
+const baseMetadata = Base[Symbol.metadata];
+assert.sameValue(Object.getPrototypeOf(baseMetadata), null);
+
+@dec class Derived extends Base { }
+const derivedMetadata = Derived[Symbol.metadata];
+assert.sameValue(Object.getPrototypeOf(derivedMetadata), baseMetadata);
diff --git a/test/language/statements/class/decorator/metadata/metadata-is-plain-object.js b/test/language/statements/class/decorator/metadata/metadata-is-plain-object.js
new file mode 100644
index 0000000000..b5e176e48e
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/metadata-is-plain-object.js
@@ -0,0 +1,32 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    The metadata object is a regular, extensible JS object.
+info: |
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+function dec() {}
+
+@dec class C {}
+const metadata = C[Symbol.metadata];
+assert(Object.isExtensible(metadata));
diff --git a/test/language/statements/class/decorator/metadata/metadata-is-same-as-context-metadata.js b/test/language/statements/class/decorator/metadata/metadata-is-same-as-context-metadata.js
new file mode 100644
index 0000000000..020f3a1bc0
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/metadata-is-same-as-context-metadata.js
@@ -0,0 +1,47 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-runtime-semantics-classdefinitionevaluation
+description: >
+    The metadata object provided to a decorator is the same one installed on the class.
+info: |
+    CreateDecoratorContextObject ( kind, name, initializers, decorationState, metadataObj [ , isStatic ] )
+
+    [...]
+    13. Perform ! CreateDataPropertyOrThrow(contextObj, "metadata", metadata).
+    14. Return contextObj.
+
+    ClassDefinitionEvaluation
+    ClassTail : ClassHeritage_opt { ClassBody_opt }
+
+    21. Let hasDecorators be false.
+    22. If decorators is not empty, set hasDecorators to true.
+    [...]
+    25. For each ClassElement e of elements, do
+      [...]
+      e. If element is a ClassElementDefinition Record, then
+        i. If e.[[Decorators]] is not empty, set hasDecorators to true.
+      [...]
+    [...]
+    29. Let metadataObj be empty.
+    30. If hasDecorators is true, then
+      a. If ClassHeritage is present, [...]
+      b. Else, let metadataParent be null.
+      c. Set metadataObj to OrdinaryObjectCreate(metadataParent).
+    [...]
+    41. If metadataObj is not empty, then
+      a. Let setMetadataResult be Completion(DefinePropertyOrThrow(F, @@metadata, PropertyDescriptor { [[Value]]: metadataObj, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true })).
+          1. If _setMetadataResult_ is an abrupt completion, then
+            1. Set the running execution context's PrivateEnvironment to _outerPrivateEnvironment_.
+            1. Return ? _setMetadataResult_.
+    [...]
+features: [decorators, decorator-metadata]
+---*/
+
+var contextObj;
+function dec(_, context) {
+  contextObj = context;
+}
+
+@dec class C {}
+assert.sameValue(C[Symbol.metadata], contextObj.metadata);
diff --git a/test/language/statements/class/decorator/metadata/metadata-prop-desc.js b/test/language/statements/class/decorator/metadata/metadata-prop-desc.js
new file mode 100644
index 0000000000..2113eceb0f
--- /dev/null
+++ b/test/language/statements/class/decorator/metadata/metadata-prop-desc.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Ron Buckton. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-createdecoratorcontextobject
+description: >
+    Property descriptor for metadata property of decorator context object.
+info: |
+    CreateDecoratorContextObject ( kind, name, initializers, decorationState, metadataObj [ , isStatic ] )
+    [...]
+    13. Perform ! CreateDataPropertyOrThrow(contextObj, "metadata", metadata).
+    14. Return contextObj.
+includes: [propertyHelper.js]
+features: [decorators, decorator-metadata]
+---*/
+
+var contextObj;
+function dec(_, context) {
+  contextObj = context;
+}
+
+@dec class C {}
+assert.sameValue(typeof contextObj.metadata, "object");
+verifyNotEnumerable(contextObj, "metadata");
+verifyWritable(contextObj, "metadata");
+verifyConfigurable(contextObj, "metadata");