diff --git a/.changeset/calm-derived-reconnect.md b/.changeset/calm-derived-reconnect.md
new file mode 100644
index 0000000000..22aa5e9357
--- /dev/null
+++ b/.changeset/calm-derived-reconnect.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: prevent duplicate reactions when reconnecting deriveds
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index d86c349445..15707533ac 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -736,7 +736,10 @@ function reconnect(derived) {
 	if (derived.deps === null) return;
 
 	for (const dep of derived.deps) {
-		(dep.reactions ??= []).push(derived);
+		var reactions = (dep.reactions ??= []);
+		if (!includes.call(reactions, derived)) {
+			reactions.push(derived);
+		}
 
 		if ((dep.f & DERIVED) !== 0 && (dep.f & CONNECTED) === 0) {
 			unfreeze_derived_effects(/** @type {Derived} */ (dep));
diff --git a/packages/svelte/tests/signals/test.ts b/packages/svelte/tests/signals/test.ts
index 285dc1b3ce..09a692c742 100644
--- a/packages/svelte/tests/signals/test.ts
+++ b/packages/svelte/tests/signals/test.ts
@@ -810,6 +810,30 @@ describe('signals', () => {
 		};
 	});
 
+	test('deriveds with changed dependencies clean up after reconnection', () => {
+		const visible = state(true);
+		const first = state(0);
+		const second = state(1);
+		const selected = state(first);
+		const value = derived(() => $.get($.get(selected)));
+
+		return () => {
+			const destroy = effect_root(() => {
+				render_effect(() => {
+					if ($.get(visible)) $.get(value);
+				});
+			});
+
+			flushSync(() => set(visible, false));
+			flushSync(() => set(selected, second));
+			flushSync(() => set(visible, true));
+
+			destroy();
+
+			assert.equal(second.reactions, null);
+		};
+	});
+
 	test('deriveds update upon reconnection #1', () => {
 		let a = state(false);
 		let b = state(false);