diff --git a/CHANGELOG.md b/CHANGELOG.md
index a27d408edf8e..eaa379867814 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@
 
 ### Fixes
 
+- `[jest-environment-jsdom, jest-environment-node]` Fix assignment of `customExportConditions` via `testEnvironmentOptions` when custom env subclass defines a default value ([#13989](https://github.com/facebook/jest/pull/13989))
+
 ### Chore & Maintenance
 
 ### Performance
diff --git a/e2e/resolve-conditions/__tests__/custom-env-conditions-method-override.test.mjs b/e2e/resolve-conditions/__tests__/custom-env-conditions-method-override.test.mjs
new file mode 100644
index 000000000000..b8318bb79192
--- /dev/null
+++ b/e2e/resolve-conditions/__tests__/custom-env-conditions-method-override.test.mjs
@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @jest-environment <rootDir>/custom-env-conditions-method-override.js
+ */
+
+import {fn} from 'fake-dual-dep';
+
+test('returns correct message', () => {
+  expect(fn()).toBe('hello from deno');
+});
diff --git a/e2e/resolve-conditions/__tests__/custom-env-override-export-conditions.test.mjs b/e2e/resolve-conditions/__tests__/custom-env-override-export-conditions.test.mjs
new file mode 100644
index 000000000000..fe084ea54525
--- /dev/null
+++ b/e2e/resolve-conditions/__tests__/custom-env-override-export-conditions.test.mjs
@@ -0,0 +1,15 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @jest-environment <rootDir>/custom-env.js
+ * @jest-environment-options {"customExportConditions": ["react-native"]}
+ */
+
+import {fn} from 'fake-dual-dep';
+
+test('returns correct message', () => {
+  expect(fn()).toBe('hello from react-native');
+});
diff --git a/e2e/resolve-conditions/__tests__/deno.test.mjs b/e2e/resolve-conditions/__tests__/custom-env.test.mjs
similarity index 87%
rename from e2e/resolve-conditions/__tests__/deno.test.mjs
rename to e2e/resolve-conditions/__tests__/custom-env.test.mjs
index 75fac0e3ea33..9f48b4071007 100644
--- a/e2e/resolve-conditions/__tests__/deno.test.mjs
+++ b/e2e/resolve-conditions/__tests__/custom-env.test.mjs
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @jest-environment <rootDir>/deno-env.js
+ * @jest-environment <rootDir>/custom-env.js
  */
 
 import {fn} from 'fake-dual-dep';
diff --git a/e2e/resolve-conditions/deno-env.js b/e2e/resolve-conditions/custom-env-conditions-method-override.js
similarity index 83%
rename from e2e/resolve-conditions/deno-env.js
rename to e2e/resolve-conditions/custom-env-conditions-method-override.js
index 137dbf487eb6..69fe9f135dd1 100644
--- a/e2e/resolve-conditions/deno-env.js
+++ b/e2e/resolve-conditions/custom-env-conditions-method-override.js
@@ -9,7 +9,7 @@
 
 const NodeEnv = require('jest-environment-node').TestEnvironment;
 
-module.exports = class DenoEnvWithConditions extends NodeEnv {
+module.exports = class CustomEnvWithConditions extends NodeEnv {
   exportConditions() {
     return ['deno'];
   }
diff --git a/e2e/resolve-conditions/custom-env.js b/e2e/resolve-conditions/custom-env.js
new file mode 100644
index 000000000000..74f83a770ea0
--- /dev/null
+++ b/e2e/resolve-conditions/custom-env.js
@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+'use strict';
+
+const NodeEnv = require('jest-environment-node').TestEnvironment;
+
+module.exports = class CustomEnvWithConditions extends NodeEnv {
+  customExportConditions = ['deno'];
+};
diff --git a/e2e/resolve-conditions/node_modules/fake-dual-dep/package.json b/e2e/resolve-conditions/node_modules/fake-dual-dep/package.json
index f868e6f55426..d574ed50d85b 100644
--- a/e2e/resolve-conditions/node_modules/fake-dual-dep/package.json
+++ b/e2e/resolve-conditions/node_modules/fake-dual-dep/package.json
@@ -6,6 +6,7 @@
       "deno": "./deno.mjs",
       "node": "./node.mjs",
       "browser": "./browser.mjs",
+      "react-native": "./react-native.js",
       "special": "./special.mjs"
     }
   }
diff --git a/e2e/resolve-conditions/node_modules/fake-dual-dep/react-native.js b/e2e/resolve-conditions/node_modules/fake-dual-dep/react-native.js
new file mode 100644
index 000000000000..7f9d697e613e
--- /dev/null
+++ b/e2e/resolve-conditions/node_modules/fake-dual-dep/react-native.js
@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+module.exports.fn = function fn() {
+  return 'hello from react-native';
+}
diff --git a/packages/jest-environment-jsdom/src/index.ts b/packages/jest-environment-jsdom/src/index.ts
index dec78d95edf4..2dbc4caaad5d 100644
--- a/packages/jest-environment-jsdom/src/index.ts
+++ b/packages/jest-environment-jsdom/src/index.ts
@@ -38,6 +38,7 @@ export default class JSDOMEnvironment implements JestEnvironment<number> {
   private errorEventListener: ((event: Event & {error: Error}) => void) | null;
   moduleMocker: ModuleMocker | null;
   customExportConditions = ['browser'];
+  private _configuredExportConditions?: Array<string>;
 
   constructor(config: JestEnvironmentConfig, context: EnvironmentContext) {
     const {projectConfig} = config;
@@ -119,7 +120,7 @@ export default class JSDOMEnvironment implements JestEnvironment<number> {
         Array.isArray(customExportConditions) &&
         customExportConditions.every(isString)
       ) {
-        this.customExportConditions = customExportConditions;
+        this._configuredExportConditions = customExportConditions;
       } else {
         throw new Error(
           'Custom export conditions specified but they are not an array of strings',
@@ -170,7 +171,7 @@ export default class JSDOMEnvironment implements JestEnvironment<number> {
   }
 
   exportConditions(): Array<string> {
-    return this.customExportConditions;
+    return this._configuredExportConditions ?? this.customExportConditions;
   }
 
   getVmContext(): Context | null {
diff --git a/packages/jest-environment-node/src/index.ts b/packages/jest-environment-node/src/index.ts
index 6d7da8c2f5d5..1b387aaffee5 100644
--- a/packages/jest-environment-node/src/index.ts
+++ b/packages/jest-environment-node/src/index.ts
@@ -64,6 +64,7 @@ export default class NodeEnvironment implements JestEnvironment<Timer> {
   global: Global.Global;
   moduleMocker: ModuleMocker | null;
   customExportConditions = ['node', 'node-addons'];
+  private _configuredExportConditions?: Array<string>;
 
   // while `context` is unused, it should always be passed
   constructor(config: JestEnvironmentConfig, _context: EnvironmentContext) {
@@ -147,7 +148,7 @@ export default class NodeEnvironment implements JestEnvironment<Timer> {
         Array.isArray(customExportConditions) &&
         customExportConditions.every(isString)
       ) {
-        this.customExportConditions = customExportConditions;
+        this._configuredExportConditions = customExportConditions;
       } else {
         throw new Error(
           'Custom export conditions specified but they are not an array of strings',
@@ -201,7 +202,7 @@ export default class NodeEnvironment implements JestEnvironment<Timer> {
   }
 
   exportConditions(): Array<string> {
-    return this.customExportConditions;
+    return this._configuredExportConditions ?? this.customExportConditions;
   }
 
   getVmContext(): Context | null {