diff --git a/packages/ses/src/get-anonymous-intrinsics.js b/packages/ses/src/get-anonymous-intrinsics.js
index f7fcd37118..1dc66f9825 100644
--- a/packages/ses/src/get-anonymous-intrinsics.js
+++ b/packages/ses/src/get-anonymous-intrinsics.js
@@ -161,5 +161,19 @@ export const getAnonymousIntrinsics = () => {
     );
   }
 
+  if (globalThis.ModuleSource) {
+    const AbstractModuleSourcePrototype = getPrototypeOf(
+      globalThis.ModuleSource.prototype,
+    );
+    intrinsics['%AbstractModuleSourcePrototype%'] =
+      AbstractModuleSourcePrototype;
+    intrinsics['%AbstractModuleSource%'] =
+      AbstractModuleSourcePrototype.constructor;
+  }
+
+  if (globalThis.ModuleSource) {
+    intrinsics['%ModuleSourcePrototype%'] = globalThis.ModuleSource.prototype;
+  }
+
   return intrinsics;
 };
diff --git a/packages/ses/src/permits-intrinsics.js b/packages/ses/src/permits-intrinsics.js
index 03f7fe2250..aefef597ce 100644
--- a/packages/ses/src/permits-intrinsics.js
+++ b/packages/ses/src/permits-intrinsics.js
@@ -212,7 +212,9 @@ export default function whitelistIntrinsics(
       }
     }
 
-    throw TypeError(`Unexpected whitelist permit ${permit} at ${path}`);
+    throw TypeError(
+      `Unexpected property ${prop} with permit ${permit} at ${path}`,
+    );
   }
 
   /*
diff --git a/packages/ses/src/permits.js b/packages/ses/src/permits.js
index 585d3c0c3f..6915f081f4 100644
--- a/packages/ses/src/permits.js
+++ b/packages/ses/src/permits.js
@@ -101,8 +101,12 @@ export const universalPropertyNames = {
 
   // ESNext
 
+  // https://github.com/tc39/proposal-source-phase-imports?tab=readme-ov-file#js-module-source
+  ModuleSource: 'ModuleSource',
+
   lockdown: 'lockdown',
   harden: 'harden',
+
   HandledPromise: 'HandledPromise', // TODO: Until Promise.delegate (see below).
 };
 
@@ -1505,6 +1509,25 @@ export const permitted = {
     resolve: fn,
   },
 
+  // https://github.com/tc39/proposal-source-phase-imports?tab=readme-ov-file#js-module-source
+  '%AbstractModuleSourcePrototype%': {
+    '@@toStringTag': getter,
+    constructor: '%AbstractModuleSource%',
+  },
+  '%AbstractModuleSource%': {
+    '[[Proto]]': '%FunctionPrototype%',
+    prototype: '%AbstractModuleSourcePrototype%',
+  },
+  '%ModuleSourcePrototype%': {
+    '[[Proto]]': '%AbstractModuleSourcePrototype%',
+    '@@toStringTag': getter,
+    constructor: 'ModuleSource',
+  },
+  ModuleSource: {
+    '[[Proto]]': '%FunctionPrototype%',
+    prototype: '%ModuleSourcePrototype%',
+  },
+
   Promise: {
     // Properties of the Promise Constructor
     '[[Proto]]': '%FunctionPrototype%',
diff --git a/packages/ses/test/module-source.test.js b/packages/ses/test/module-source.test.js
index dfdd0c2772..69a2504faf 100644
--- a/packages/ses/test/module-source.test.js
+++ b/packages/ses/test/module-source.test.js
@@ -47,4 +47,5 @@ test('module source constructor', t => {
 
 test('ModuleSource is a shared intrinsic', t => {
   t.truthy(ModuleSource === new Compartment().globalThis.ModuleSource);
+  t.truthy(Object.isFrozen(ModuleSource));
 });