diff --git a/packages/language-service/src/diagnostics.ts b/packages/language-service/src/diagnostics.ts
index 755a7e1df9..2ee1e31841 100644
--- a/packages/language-service/src/diagnostics.ts
+++ b/packages/language-service/src/diagnostics.ts
@@ -71,9 +71,12 @@ export function getDeclarationDiagnostics(
           report(
               `Component '${declaration.type.name}' is not included in a module and will not be available inside a template. Consider adding it to a NgModule declaration`);
         }
-        if (!declaration.metadata.template !.template &&
-            !declaration.metadata.template !.templateUrl) {
-          report(`Component ${declaration.type.name} must have a template or templateUrl`);
+        const {template, templateUrl} = declaration.metadata.template !;
+        if (template === null && !templateUrl) {
+          report(`Component '${declaration.type.name}' must have a template or templateUrl`);
+        } else if (template && templateUrl) {
+          report(
+              `Component '${declaration.type.name}' must not have both template and templateUrl`);
         }
       } else {
         if (!directives) {
diff --git a/packages/language-service/test/diagnostics_spec.ts b/packages/language-service/test/diagnostics_spec.ts
index eab1c1e6ac..07a77c2872 100644
--- a/packages/language-service/test/diagnostics_spec.ts
+++ b/packages/language-service/test/diagnostics_spec.ts
@@ -175,6 +175,22 @@ describe('diagnostics', () => {
       });
     });
 
+    // Issue #19406
+    it('should allow empty template', () => {
+      const appComponent = `
+        import { Component } from '@angular/core';
+
+        @Component({
+          template : '',
+        })
+        export class AppComponent {}
+      `;
+      const fileName = '/app/app.component.ts';
+      mockHost.override(fileName, appComponent);
+      const diagnostics = ngService.getDiagnostics(fileName);
+      expect(diagnostics).toEqual([]);
+    });
+
     // Issue #15460
     it('should be able to find members defined on an ancestor type', () => {
       const app_component = `