diff --git a/packages/compiler-cli/src/ngtsc/typecheck/src/type_parameter_emitter.ts b/packages/compiler-cli/src/ngtsc/typecheck/src/type_parameter_emitter.ts
index c973742cea..018b36a3f8 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/src/type_parameter_emitter.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/src/type_parameter_emitter.ts
@@ -32,14 +32,18 @@ export class TypeParameterEmitter {
     }
 
     return this.typeParameters.every(typeParam => {
-      if (typeParam.constraint === undefined) {
-        return true;
-      }
-
-      return canEmitType(typeParam.constraint, type => this.resolveTypeReference(type));
+      return this.canEmitType(typeParam.constraint) && this.canEmitType(typeParam.default);
     });
   }
 
+  private canEmitType(type: ts.TypeNode|undefined): boolean {
+    if (type === undefined) {
+      return true;
+    }
+
+    return canEmitType(type, typeReference => this.resolveTypeReference(typeReference));
+  }
+
   /**
    * Emits the type parameters using the provided emitter function for `Reference`s.
    */
@@ -53,12 +57,14 @@ export class TypeParameterEmitter {
     return this.typeParameters.map(typeParam => {
       const constraint =
           typeParam.constraint !== undefined ? emitter.emitType(typeParam.constraint) : undefined;
+      const defaultType =
+          typeParam.default !== undefined ? emitter.emitType(typeParam.default) : undefined;
 
       return ts.updateTypeParameterDeclaration(
           /* node */ typeParam,
           /* name */ typeParam.name,
           /* constraint */ constraint,
-          /* defaultType */ typeParam.default);
+          /* defaultType */ defaultType);
     });
   }
 
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/test/type_parameter_emitter_spec.ts b/packages/compiler-cli/src/ngtsc/typecheck/test/type_parameter_emitter_spec.ts
index 03d2b15b09..4857964057 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/test/type_parameter_emitter_spec.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/test/type_parameter_emitter_spec.ts
@@ -222,5 +222,32 @@ runInEachFileSystem(() => {
       expect(emitter.canEmit()).toBe(true);
       expect(emit(emitter)).toEqual('<T extends test.MyType>');
     });
+
+    it('transforms generic type parameter defaults', () => {
+      const additionalFiles: TestFile[] = [{
+        name: absoluteFrom('/node_modules/types/index.d.ts'),
+        contents: `export declare type MyType = string;`,
+      }];
+      const emitter = createEmitter(
+          `
+          import {MyType} from 'types';
+
+          export class TestClass<T extends MyType = MyType> {}`,
+          additionalFiles);
+
+      expect(emitter.canEmit()).toBe(true);
+      expect(emit(emitter)).toEqual('<T extends test.MyType = test.MyType>');
+    });
+
+    it('cannot emit when a type parameter default cannot be emitted', () => {
+      const emitter = createEmitter(`
+          interface Local {}
+
+          export class TestClass<T extends object = Local> {}`);
+
+      expect(emitter.canEmit()).toBe(false);
+      expect(() => emit(emitter))
+          .toThrowError('A type reference to emit must be imported from an absolute module');
+    });
   });
 });