diff --git a/src/Illuminate/Routing/ResponseFactory.php b/src/Illuminate/Routing/ResponseFactory.php
index a78459c47197..7c91102b347c 100644
--- a/src/Illuminate/Routing/ResponseFactory.php
+++ b/src/Illuminate/Routing/ResponseFactory.php
@@ -203,7 +203,7 @@ public function stream($callback, $status = 200, array $headers = [])
             return new StreamedResponse(function () use ($callback) {
                 foreach ($callback() as $chunk) {
                     echo $chunk;
-                    ob_flush();
+                    when(ob_get_level() > 0, fn () => ob_flush());
                     flush();
                 }
             }, $status, array_merge($headers, ['X-Accel-Buffering' => 'no']));