diff --git a/src/runtime/internal/dev.ts b/src/runtime/internal/dev.ts
index 76d68086c841..b59e0631a938 100644
--- a/src/runtime/internal/dev.ts
+++ b/src/runtime/internal/dev.ts
@@ -1,5 +1,6 @@
 import { custom_event, append, append_hydration, insert, insert_hydration, detach, listen, attr } from './dom';
 import { SvelteComponent } from './Component';
+import { current_component } from './lifecycle';
 
 export function dispatch_dev<T=any>(type: string, detail?: T) {
 	document.dispatchEvent(custom_event(type, { version: '__VERSION__', ...detail }, true));
@@ -155,6 +156,13 @@ export class SvelteComponentDev extends SvelteComponent {
 			throw new Error("'target' is a required option");
 		}
 
+		if (!options.target && !current_component) {
+			throw new Error(
+				'Multiple Svelte instances detected. This can happen if you use Svelte components which are precompiled to JavaScript. ' +
+					"Ensure to use the raw Svelte version of these components, or set the 'target' option instead"
+			);
+		}
+
 		super();
 	}