diff --git a/packages/editor/src/ui/inspector/provider.tsx b/packages/editor/src/ui/inspector/provider.tsx
index 8d7de715a8..e6863305d0 100644
--- a/packages/editor/src/ui/inspector/provider.tsx
+++ b/packages/editor/src/ui/inspector/provider.tsx
@@ -131,6 +131,18 @@ export function useInspector() {
 export function InspectorProvider({ children }: RootProps) {
   const { editor } = useCurrentEditor();
 
+  if (editor) {
+    const hasEmailTheming = editor.extensionManager.extensions.some(
+      (extension) => extension.name === 'theming',
+    );
+    if (!hasEmailTheming) {
+      throw new Error(
+        'Inspector.Provider requires the EmailTheming extension to be added to your editor. ' +
+          'Please add EmailTheming (or EmailTheming.configure({ ... })) to your editor extensions.',
+      );
+    }
+  }
+
   const target = useEditorState({
     editor,
     selector(context): InspectorTarget {