diff --git a/docs/fast-refresh.md b/docs/fast-refresh.md
index 89010b75065..73c69b33d70 100644
--- a/docs/fast-refresh.md
+++ b/docs/fast-refresh.md
@@ -45,3 +45,5 @@ Hooks with dependencies—such as `useEffect`, `useMemo`, and `useCallback`—wi
 For example, when you edit `useMemo(() => x * 2, [x])` to `useMemo(() => x * 10, [x])`, it will re-run even though `x` (the dependency) has not changed. If React didn't do that, your edit wouldn't reflect on the screen!
 
 Sometimes, this can lead to unexpected results. For example, even a `useEffect` with an empty array of dependencies would still re-run once during Fast Refresh. However, writing code resilient to an occasional re-running of `useEffect` is a good practice even without Fast Refresh. This makes it easier for you to later introduce new dependencies to it.
+
+Fast Refresh is not the only reason an Effect may run again during development. When [Strict Mode](https://react.dev/reference/react/StrictMode#fixing-bugs-found-by-re-running-effects-in-development) is enabled at the application root, React runs an additional development-only setup and cleanup cycle to help find missing cleanup. Fast Refresh re-runs Hooks after a code edit, whereas the Strict Mode check can run when a component first mounts. In both cases, Effects should implement complete cleanup and tolerate being restarted.