diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index d641cbd4b65e7..68133ac5f1e40 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -7505,7 +7505,11 @@ namespace Parser {
             case SyntaxKind.LetKeyword:
             case SyntaxKind.ConstKeyword:
             case SyntaxKind.UsingKeyword:
+                return parseVariableStatement(pos, hasJSDoc, modifiersIn);
             case SyntaxKind.AwaitKeyword:
+                if (!isAwaitUsingDeclaration()) {
+                    break;
+                }
                 return parseVariableStatement(pos, hasJSDoc, modifiersIn);
             case SyntaxKind.FunctionKeyword:
                 return parseFunctionDeclaration(pos, hasJSDoc, modifiersIn);
@@ -7534,17 +7538,16 @@ namespace Parser {
                     default:
                         return parseExportDeclaration(pos, hasJSDoc, modifiersIn);
                 }
-            default:
-                if (modifiersIn) {
-                    // We reached this point because we encountered decorators and/or modifiers and assumed a declaration
-                    // would follow. For recovery and error reporting purposes, return an incomplete declaration.
-                    const missing = createMissingNode<MissingDeclaration>(SyntaxKind.MissingDeclaration, /*reportAtCurrentPosition*/ true, Diagnostics.Declaration_expected);
-                    setTextRangePos(missing, pos);
-                    (missing as Mutable<MissingDeclaration>).modifiers = modifiersIn;
-                    return missing;
-                }
-                return undefined!; // TODO: GH#18217
         }
+        if (modifiersIn) {
+            // We reached this point because we encountered decorators and/or modifiers and assumed a declaration
+            // would follow. For recovery and error reporting purposes, return an incomplete declaration.
+            const missing = createMissingNode<MissingDeclaration>(SyntaxKind.MissingDeclaration, /*reportAtCurrentPosition*/ true, Diagnostics.Declaration_expected);
+            setTextRangePos(missing, pos);
+            (missing as Mutable<MissingDeclaration>).modifiers = modifiersIn;
+            return missing;
+        }
+        return undefined!; // TODO: GH#18217
     }
 
     function nextTokenIsStringLiteral() {
@@ -7677,7 +7680,9 @@ namespace Parser {
                 flags |= NodeFlags.Using;
                 break;
             case SyntaxKind.AwaitKeyword:
-                Debug.assert(isAwaitUsingDeclaration());
+                if (!isAwaitUsingDeclaration()) {
+                    break;
+                }
                 flags |= NodeFlags.AwaitUsing;
                 nextToken();
                 break;
diff --git a/tests/baselines/reference/decoratorOnAwait.errors.txt b/tests/baselines/reference/decoratorOnAwait.errors.txt
new file mode 100644
index 0000000000000..72a64f3c7d865
--- /dev/null
+++ b/tests/baselines/reference/decoratorOnAwait.errors.txt
@@ -0,0 +1,11 @@
+decoratorOnAwait.ts(3,5): error TS1146: Declaration expected.
+
+
+==== decoratorOnAwait.ts (1 errors) ====
+    declare function dec<T>(target: T): T;
+    
+    @dec
+        
+!!! error TS1146: Declaration expected.
+    await 1
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/decoratorOnAwait.js b/tests/baselines/reference/decoratorOnAwait.js
new file mode 100644
index 0000000000000..c8a0546e388ff
--- /dev/null
+++ b/tests/baselines/reference/decoratorOnAwait.js
@@ -0,0 +1,11 @@
+//// [tests/cases/conformance/decorators/invalid/decoratorOnAwait.ts] ////
+
+//// [decoratorOnAwait.ts]
+declare function dec<T>(target: T): T;
+
+@dec
+await 1
+
+
+//// [decoratorOnAwait.js]
+await 1;
diff --git a/tests/baselines/reference/decoratorOnAwait.symbols b/tests/baselines/reference/decoratorOnAwait.symbols
new file mode 100644
index 0000000000000..a2c9ac6a3a10f
--- /dev/null
+++ b/tests/baselines/reference/decoratorOnAwait.symbols
@@ -0,0 +1,15 @@
+//// [tests/cases/conformance/decorators/invalid/decoratorOnAwait.ts] ////
+
+=== decoratorOnAwait.ts ===
+declare function dec<T>(target: T): T;
+>dec : Symbol(dec, Decl(decoratorOnAwait.ts, 0, 0))
+>T : Symbol(T, Decl(decoratorOnAwait.ts, 0, 21))
+>target : Symbol(target, Decl(decoratorOnAwait.ts, 0, 24))
+>T : Symbol(T, Decl(decoratorOnAwait.ts, 0, 21))
+>T : Symbol(T, Decl(decoratorOnAwait.ts, 0, 21))
+
+@dec
+>dec : Symbol(dec, Decl(decoratorOnAwait.ts, 0, 0))
+
+await 1
+
diff --git a/tests/baselines/reference/decoratorOnAwait.types b/tests/baselines/reference/decoratorOnAwait.types
new file mode 100644
index 0000000000000..f5a3ec4681d42
--- /dev/null
+++ b/tests/baselines/reference/decoratorOnAwait.types
@@ -0,0 +1,19 @@
+//// [tests/cases/conformance/decorators/invalid/decoratorOnAwait.ts] ////
+
+=== decoratorOnAwait.ts ===
+declare function dec<T>(target: T): T;
+>dec : <T>(target: T) => T
+>    : ^ ^^      ^^ ^^^^^ 
+>target : T
+>       : ^
+
+@dec
+>dec : <T>(target: T) => T
+>    : ^ ^^      ^^ ^^^^^ 
+
+await 1
+>await 1 : 1
+>        : ^
+>1 : 1
+>  : ^
+
diff --git a/tests/baselines/reference/decoratorOnUsing.errors.txt b/tests/baselines/reference/decoratorOnUsing.errors.txt
new file mode 100644
index 0000000000000..1861fa34a32e8
--- /dev/null
+++ b/tests/baselines/reference/decoratorOnUsing.errors.txt
@@ -0,0 +1,14 @@
+decoratorOnUsing.ts(4,7): error TS1134: Variable declaration expected.
+
+
+==== decoratorOnUsing.ts (1 errors) ====
+    declare function dec<T>(target: T): T;
+    
+    @dec
+    using 1
+          ~
+!!! error TS1134: Variable declaration expected.
+    
+    @dec
+    using x
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/decoratorOnUsing.js b/tests/baselines/reference/decoratorOnUsing.js
new file mode 100644
index 0000000000000..47b470c658d9b
--- /dev/null
+++ b/tests/baselines/reference/decoratorOnUsing.js
@@ -0,0 +1,16 @@
+//// [tests/cases/conformance/decorators/invalid/decoratorOnUsing.ts] ////
+
+//// [decoratorOnUsing.ts]
+declare function dec<T>(target: T): T;
+
+@dec
+using 1
+
+@dec
+using x
+
+
+//// [decoratorOnUsing.js]
+using ;
+1;
+using x;
diff --git a/tests/baselines/reference/decoratorOnUsing.symbols b/tests/baselines/reference/decoratorOnUsing.symbols
new file mode 100644
index 0000000000000..a173c7e318502
--- /dev/null
+++ b/tests/baselines/reference/decoratorOnUsing.symbols
@@ -0,0 +1,21 @@
+//// [tests/cases/conformance/decorators/invalid/decoratorOnUsing.ts] ////
+
+=== decoratorOnUsing.ts ===
+declare function dec<T>(target: T): T;
+>dec : Symbol(dec, Decl(decoratorOnUsing.ts, 0, 0))
+>T : Symbol(T, Decl(decoratorOnUsing.ts, 0, 21))
+>target : Symbol(target, Decl(decoratorOnUsing.ts, 0, 24))
+>T : Symbol(T, Decl(decoratorOnUsing.ts, 0, 21))
+>T : Symbol(T, Decl(decoratorOnUsing.ts, 0, 21))
+
+@dec
+>dec : Symbol(dec, Decl(decoratorOnUsing.ts, 0, 0))
+
+using 1
+
+@dec
+>dec : Symbol(dec, Decl(decoratorOnUsing.ts, 0, 0))
+
+using x
+>x : Symbol(x, Decl(decoratorOnUsing.ts, 6, 5))
+
diff --git a/tests/baselines/reference/decoratorOnUsing.types b/tests/baselines/reference/decoratorOnUsing.types
new file mode 100644
index 0000000000000..cb108be89851e
--- /dev/null
+++ b/tests/baselines/reference/decoratorOnUsing.types
@@ -0,0 +1,25 @@
+//// [tests/cases/conformance/decorators/invalid/decoratorOnUsing.ts] ////
+
+=== decoratorOnUsing.ts ===
+declare function dec<T>(target: T): T;
+>dec : <T>(target: T) => T
+>    : ^ ^^      ^^ ^^^^^ 
+>target : T
+>       : ^
+
+@dec
+>dec : <T>(target: T) => T
+>    : ^ ^^      ^^ ^^^^^ 
+
+using 1
+>1 : 1
+>  : ^
+
+@dec
+>dec : <T>(target: T) => T
+>    : ^ ^^      ^^ ^^^^^ 
+
+using x
+>x : any
+>  : ^^^
+
diff --git a/tests/cases/conformance/decorators/invalid/decoratorOnAwait.ts b/tests/cases/conformance/decorators/invalid/decoratorOnAwait.ts
new file mode 100644
index 0000000000000..71fc65e34a036
--- /dev/null
+++ b/tests/cases/conformance/decorators/invalid/decoratorOnAwait.ts
@@ -0,0 +1,4 @@
+declare function dec<T>(target: T): T;
+
+@dec
+await 1
diff --git a/tests/cases/conformance/decorators/invalid/decoratorOnUsing.ts b/tests/cases/conformance/decorators/invalid/decoratorOnUsing.ts
new file mode 100644
index 0000000000000..815da8de4de27
--- /dev/null
+++ b/tests/cases/conformance/decorators/invalid/decoratorOnUsing.ts
@@ -0,0 +1,8 @@
+// @target: esnext
+declare function dec<T>(target: T): T;
+
+@dec
+using 1
+
+@dec
+using x