diff --git a/packages/core/src/reflection/reflection_capabilities.ts b/packages/core/src/reflection/reflection_capabilities.ts
index 1e6123e7de..70d67a5cf9 100644
--- a/packages/core/src/reflection/reflection_capabilities.ts
+++ b/packages/core/src/reflection/reflection_capabilities.ts
@@ -252,7 +252,7 @@ function convertTsickleDecoratorIntoMetadata(decoratorInvocations: any[]): any[]
 }
 
 function getParentCtor(ctor: Function): Type<any> {
-  const parentProto = Object.getPrototypeOf(ctor.prototype);
+  const parentProto = ctor.prototype ? Object.getPrototypeOf(ctor.prototype) : null;
   const parentCtor = parentProto ? parentProto.constructor : null;
   // Note: We always use `Object` as the null value
   // to simplify checking later on.
diff --git a/packages/core/test/reflection/reflector_spec.ts b/packages/core/test/reflection/reflector_spec.ts
index 0ca80cd81a..7c77e5033a 100644
--- a/packages/core/test/reflection/reflector_spec.ts
+++ b/packages/core/test/reflection/reflector_spec.ts
@@ -181,6 +181,13 @@ class TestObj {
         expect(DELEGATE_CTOR.exec(ChildNoCtorPrivateProps.toString())).toBeTruthy();
         expect(DELEGATE_CTOR.exec(ChildWithCtor.toString())).toBeFalsy();
       });
+
+      it('should not throw when no prototype on type', () => {
+        // Cannot test arrow function here due to the compilation
+        const dummyArrowFn = function() {};
+        Object.defineProperty(dummyArrowFn, 'prototype', {value: undefined});
+        expect(() => reflector.annotations(dummyArrowFn as any)).not.toThrow();
+      });
     });
 
     describe('inheritance with decorators', () => {