diff --git a/public/app/core/services/toggleTheme.ts b/public/app/core/services/toggleTheme.ts
index 307dfea48db..0836b3cd1a8 100644
--- a/public/app/core/services/toggleTheme.ts
+++ b/public/app/core/services/toggleTheme.ts
@@ -3,6 +3,7 @@ import { ThemeChangedEvent } from 'app/types/events';
 import appEvents from '../app_events';
 import { config } from '../config';
 import { PreferencesService } from './PreferencesService';
+import { contextSrv } from '../core';
 
 export async function toggleTheme(runtimeOnly: boolean) {
   const currentTheme = config.theme;
@@ -32,6 +33,10 @@ export async function toggleTheme(runtimeOnly: boolean) {
     }
   }
 
+  if (!contextSrv.isSignedIn) {
+    return;
+  }
+
   // Persist new theme
   const service = new PreferencesService('user');
   const currentPref = await service.load();