diff --git a/.changeset/polite-melons-tickle.md b/.changeset/polite-melons-tickle.md
new file mode 100644
index 0000000000..42967ea936
--- /dev/null
+++ b/.changeset/polite-melons-tickle.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+chore: avoid microtasks when flushing sync
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 7a926bf624..2375dc0a63 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -823,6 +823,8 @@ export function flushSync(fn) {
 	if (fn) {
 		is_flushing = true;
 		flush_queued_root_effects();
+
+		is_flushing = true;
 		result = fn();
 	}