diff --git a/chrome/renderer/media/chrome_speech_recognition_client.cc b/chrome/renderer/media/chrome_speech_recognition_client.cc
index 7332f21f82072..d7988d87aa45b 100644
--- a/chrome/renderer/media/chrome_speech_recognition_client.cc
+++ b/chrome/renderer/media/chrome_speech_recognition_client.cc
@@ -102,11 +102,21 @@ bool ChromeSpeechRecognitionClient::IsSpeechRecognitionAvailable() {
 // existing callback.
 void ChromeSpeechRecognitionClient::SetOnReadyCallback(
     SpeechRecognitionClient::OnReadyCallback callback) {
-  on_ready_callback_ = std::move(callback);
-
-  // Immediately run the callback if speech recognition is already available.
-  if (IsSpeechRecognitionAvailable() && on_ready_callback_)
-    std::move(on_ready_callback_).Run();
+  // SetOnReadyCallback() is called from the media sequence
+  // (AudioRendererImpl::Initialize) while OnRecognizerBound() runs on the
+  // main thread; guard on_ready_callback_ with the existing lock and only
+  // Run() outside the lock to avoid re-entrancy.
+  SpeechRecognitionClient::OnReadyCallback to_run;
+  {
+    base::AutoLock auto_lock(is_recognizer_bound_lock_);
+    on_ready_callback_ = std::move(callback);
+    if (is_recognizer_bound_) {
+      to_run = std::move(on_ready_callback_);
+    }
+  }
+  if (to_run) {
+    std::move(to_run).Run();
+  }
 }
 
 void ChromeSpeechRecognitionClient::Reconfigure(
@@ -118,15 +128,20 @@ void ChromeSpeechRecognitionClient::Reconfigure(
 
 void ChromeSpeechRecognitionClient::OnRecognizerBound(
     bool is_multichannel_supported) {
+  SpeechRecognitionClient::OnReadyCallback to_run;
   {
     base::AutoLock auto_lock(is_recognizer_bound_lock_);
     is_recognizer_bound_ = true;
+    // Extract under lock; SetOnReadyCallback() may be running concurrently on
+    // the media sequence.
+    to_run = std::move(on_ready_callback_);
   }
 
   is_multichannel_supported_ = is_multichannel_supported;
 
-  if (on_ready_callback_)
-    std::move(on_ready_callback_).Run();
+  if (to_run) {
+    std::move(to_run).Run();
+  }
 }
 
 void ChromeSpeechRecognitionClient::SpeechRecognitionAvailabilityChanged(
diff --git a/chrome/renderer/media/chrome_speech_recognition_client.h b/chrome/renderer/media/chrome_speech_recognition_client.h
index 20d2497d6eba6..03cac02a9f19c 100644
--- a/chrome/renderer/media/chrome_speech_recognition_client.h
+++ b/chrome/renderer/media/chrome_speech_recognition_client.h
@@ -105,7 +105,8 @@ class ChromeSpeechRecognitionClient
 
   ChromeSpeechRecognitionClient::InitializeCallback initialize_callback_;
 
-  media::SpeechRecognitionClient::OnReadyCallback on_ready_callback_;
+  media::SpeechRecognitionClient::OnReadyCallback on_ready_callback_
+      GUARDED_BY(is_recognizer_bound_lock_);
 
   base::RepeatingClosure reset_callback_;