diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index c17cc4ef9ca01..c0dd121d3c825 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -859,6 +859,9 @@ const commandOptionsWithoutBuild: CommandLineOption[] = [
     {
         name: "isolatedModules",
         type: "boolean",
+        affectsSemanticDiagnostics: true,
+        affectsEmit: true,
+        affectsBuildInfo: true,
         category: Diagnostics.Interop_Constraints,
         description: Diagnostics.Ensure_that_each_file_can_be_safely_transpiled_without_relying_on_other_imports,
         transpileOptionValue: true,
diff --git a/src/testRunner/unittests/tscWatch/programUpdates.ts b/src/testRunner/unittests/tscWatch/programUpdates.ts
index fed193fbe900c..0d13642b58db7 100644
--- a/src/testRunner/unittests/tscWatch/programUpdates.ts
+++ b/src/testRunner/unittests/tscWatch/programUpdates.ts
@@ -2488,4 +2488,51 @@ import { x } from "../b";`,
             },
         ],
     });
+
+    verifyTscWatch({
+        scenario,
+        subScenario: "toggling isolatedModules re-emits const enums",
+        commandLineArgs: ["-w"],
+        sys: () => {
+            const enumFile: File = {
+                path: `/user/username/projects/myproject/a.ts`,
+                content: `const enum TestEnum { a = 1, b = 3, c = 5 }
+const x = TestEnum.b;`,
+            };
+            const configFile: File = {
+                path: `/user/username/projects/myproject/tsconfig.json`,
+                content: jsonToReadableText({
+                    compilerOptions: {},
+                }),
+            };
+            return TestServerHost.createWatchedSystem(
+                [enumFile, configFile],
+                { currentDirectory: "/user/username/projects/myproject" },
+            );
+        },
+        edits: [
+            {
+                caption: "Enable isolatedModules — const enum should no longer be inlined",
+                edit: sys =>
+                    sys.writeFile(
+                        `/user/username/projects/myproject/tsconfig.json`,
+                        jsonToReadableText({
+                            compilerOptions: { isolatedModules: true },
+                        }),
+                    ),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+            {
+                caption: "Disable isolatedModules — const enum should be inlined again",
+                edit: sys =>
+                    sys.writeFile(
+                        `/user/username/projects/myproject/tsconfig.json`,
+                        jsonToReadableText({
+                            compilerOptions: { isolatedModules: false },
+                        }),
+                    ),
+                timeouts: sys => sys.runQueuedTimeoutCallbacks(),
+            },
+        ],
+    });
 });
diff --git a/tests/baselines/reference/tscWatch/programUpdates/toggling-isolatedModules-re-emits-const-enums.js b/tests/baselines/reference/tscWatch/programUpdates/toggling-isolatedModules-re-emits-const-enums.js
new file mode 100644
index 0000000000000..c0384ecf096c2
--- /dev/null
+++ b/tests/baselines/reference/tscWatch/programUpdates/toggling-isolatedModules-re-emits-const-enums.js
@@ -0,0 +1,192 @@
+currentDirectory:: /user/username/projects/myproject useCaseSensitiveFileNames:: false
+Input::
+//// [/user/username/projects/myproject/a.ts]
+const enum TestEnum { a = 1, b = 3, c = 5 }
+const x = TestEnum.b;
+
+//// [/user/username/projects/myproject/tsconfig.json]
+{
+  "compilerOptions": {}
+}
+
+//// [/home/src/tslibs/TS/Lib/lib.d.ts]
+interface Boolean {}
+interface Function {}
+interface CallableFunction {}
+interface NewableFunction {}
+interface IArguments {}
+interface Number { toExponential: any; }
+interface Object {}
+interface RegExp {}
+interface String { charAt: any; }
+interface Array<T> { length: number; [n: number]: T; }
+interface ReadonlyArray<T> {}
+declare const console: { log(msg: any): void; };
+
+
+/home/src/tslibs/TS/Lib/tsc.js -w
+Output::
+>> Screen clear
+[HH:MM:SS AM] Starting compilation in watch mode...
+
+[HH:MM:SS AM] Found 0 errors. Watching for file changes.
+
+
+
+//// [/home/src/tslibs/TS/Lib/lib.es2025.full.d.ts] *Lib*
+
+//// [/user/username/projects/myproject/a.js]
+"use strict";
+const x = 3 /* TestEnum.b */;
+
+
+
+FsWatches::
+/home/src/tslibs/TS/Lib/lib.es2025.full.d.ts: *new*
+  {}
+/user/username/projects/myproject/a.ts: *new*
+  {}
+/user/username/projects/myproject/tsconfig.json: *new*
+  {}
+
+FsWatchesRecursive::
+/user/username/projects/myproject: *new*
+  {}
+
+Program root files: [
+  "/user/username/projects/myproject/a.ts"
+]
+Program options: {
+  "watch": true,
+  "configFilePath": "/user/username/projects/myproject/tsconfig.json"
+}
+Program structureReused: Not
+Program files::
+/home/src/tslibs/TS/Lib/lib.es2025.full.d.ts
+/user/username/projects/myproject/a.ts
+
+Semantic diagnostics in builder refreshed for::
+/home/src/tslibs/TS/Lib/lib.es2025.full.d.ts
+/user/username/projects/myproject/a.ts
+
+Shape signatures in builder refreshed for::
+/home/src/tslibs/ts/lib/lib.es2025.full.d.ts (used version)
+/user/username/projects/myproject/a.ts (used version)
+
+exitCode:: ExitStatus.undefined
+
+Change:: Enable isolatedModules — const enum should no longer be inlined
+
+Input::
+//// [/user/username/projects/myproject/tsconfig.json]
+{
+  "compilerOptions": {
+    "isolatedModules": true
+  }
+}
+
+
+Timeout callback:: count: 1
+1: timerToUpdateProgram *new*
+
+Before running Timeout callback:: count: 1
+1: timerToUpdateProgram
+
+Host is moving to new time
+After running Timeout callback:: count: 0
+Output::
+>> Screen clear
+[HH:MM:SS AM] File change detected. Starting incremental compilation...
+
+[HH:MM:SS AM] Found 0 errors. Watching for file changes.
+
+
+
+//// [/user/username/projects/myproject/a.js]
+"use strict";
+var TestEnum;
+(function (TestEnum) {
+    TestEnum[TestEnum["a"] = 1] = "a";
+    TestEnum[TestEnum["b"] = 3] = "b";
+    TestEnum[TestEnum["c"] = 5] = "c";
+})(TestEnum || (TestEnum = {}));
+const x = TestEnum.b;
+
+
+
+
+Program root files: [
+  "/user/username/projects/myproject/a.ts"
+]
+Program options: {
+  "isolatedModules": true,
+  "watch": true,
+  "configFilePath": "/user/username/projects/myproject/tsconfig.json"
+}
+Program structureReused: Completely
+Program files::
+/home/src/tslibs/TS/Lib/lib.es2025.full.d.ts
+/user/username/projects/myproject/a.ts
+
+Semantic diagnostics in builder refreshed for::
+/home/src/tslibs/TS/Lib/lib.es2025.full.d.ts
+/user/username/projects/myproject/a.ts
+
+No shapes updated in the builder::
+
+exitCode:: ExitStatus.undefined
+
+Change:: Disable isolatedModules — const enum should be inlined again
+
+Input::
+//// [/user/username/projects/myproject/tsconfig.json]
+{
+  "compilerOptions": {
+    "isolatedModules": false
+  }
+}
+
+
+Timeout callback:: count: 1
+2: timerToUpdateProgram *new*
+
+Before running Timeout callback:: count: 1
+2: timerToUpdateProgram
+
+Host is moving to new time
+After running Timeout callback:: count: 0
+Output::
+>> Screen clear
+[HH:MM:SS AM] File change detected. Starting incremental compilation...
+
+[HH:MM:SS AM] Found 0 errors. Watching for file changes.
+
+
+
+//// [/user/username/projects/myproject/a.js]
+"use strict";
+const x = 3 /* TestEnum.b */;
+
+
+
+
+Program root files: [
+  "/user/username/projects/myproject/a.ts"
+]
+Program options: {
+  "isolatedModules": false,
+  "watch": true,
+  "configFilePath": "/user/username/projects/myproject/tsconfig.json"
+}
+Program structureReused: Completely
+Program files::
+/home/src/tslibs/TS/Lib/lib.es2025.full.d.ts
+/user/username/projects/myproject/a.ts
+
+Semantic diagnostics in builder refreshed for::
+/home/src/tslibs/TS/Lib/lib.es2025.full.d.ts
+/user/username/projects/myproject/a.ts
+
+No shapes updated in the builder::
+
+exitCode:: ExitStatus.undefined