diff --git a/tools/profiler/TableTicker.cpp b/tools/profiler/TableTicker.cpp
index 78204af6bb6..80fd6ed837e 100644
--- a/tools/profiler/TableTicker.cpp
+++ b/tools/profiler/TableTicker.cpp
@@ -283,13 +283,15 @@ void TableTicker::StreamJSObject(JSStreamWriter& b)
         }
       }
 
-      // Send a event asking any subprocesses (plugins) to
-      // give us their information
-      SubprocessClosure closure(&b);
-      nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
-      if (os) {
-        nsRefPtr<ProfileSaveEvent> pse = new ProfileSaveEvent(SubProcessCallback, &closure);
-        os->NotifyObservers(pse, "profiler-subprocess", nullptr);
+      if (Sampler::CanNotifyObservers()) {
+        // Send a event asking any subprocesses (plugins) to
+        // give us their information
+        SubprocessClosure closure(&b);
+        nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+        if (os) {
+          nsRefPtr<ProfileSaveEvent> pse = new ProfileSaveEvent(SubProcessCallback, &closure);
+          os->NotifyObservers(pse, "profiler-subprocess", nullptr);
+        }
       }
 
   #if defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
@@ -306,7 +308,6 @@ void TableTicker::StreamJSObject(JSStreamWriter& b)
     b.EndArray();
 
   b.EndObject();
-
 }
 
 // END SaveProfileTask et al
diff --git a/tools/profiler/platform.cpp b/tools/profiler/platform.cpp
index 5b01c42daba..5b5fd5d1c96 100644
--- a/tools/profiler/platform.cpp
+++ b/tools/profiler/platform.cpp
@@ -698,9 +698,11 @@ void mozilla_sampler_start(int aProfileEntries, double aInterval,
 
   sIsProfiling = true;
 
-  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
-  if (os)
-    os->NotifyObservers(nullptr, "profiler-started", nullptr);
+  if (Sampler::CanNotifyObservers()) {
+    nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+    if (os)
+      os->NotifyObservers(nullptr, "profiler-started", nullptr);
+  }
 
   LOG("END   mozilla_sampler_start");
 }
@@ -749,9 +751,11 @@ void mozilla_sampler_stop()
 
   sIsProfiling = false;
 
-  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
-  if (os)
-    os->NotifyObservers(nullptr, "profiler-stopped", nullptr);
+  if (Sampler::CanNotifyObservers()) {
+    nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+    if (os)
+      os->NotifyObservers(nullptr, "profiler-stopped", nullptr);
+  }
 
   LOG("END   mozilla_sampler_stop");
 }
diff --git a/tools/profiler/platform.h b/tools/profiler/platform.h
index c0925c5a984..ea401cc005c 100644
--- a/tools/profiler/platform.h
+++ b/tools/profiler/platform.h
@@ -44,6 +44,7 @@
 #include "mozilla/unused.h"
 #include "mozilla/TimeStamp.h"
 #include "mozilla/Mutex.h"
+#include "MainThreadUtils.h"
 #include "PlatformMacros.h"
 #include "v8-support.h"
 #include <vector>
@@ -353,6 +354,17 @@ class Sampler {
   static void SetActiveSampler(TableTicker* sampler) { sActiveSampler = sampler; }
 
   static mozilla::Mutex* sRegisteredThreadsMutex;
+
+  static bool CanNotifyObservers() {
+#if defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
+    // Android ANR reporter uses the profiler off the main thread
+    return NS_IsMainThread();
+#else
+    MOZ_ASSERT(NS_IsMainThread());
+    return true;
+#endif
+  }
+
  protected:
   static std::vector<ThreadInfo*>* sRegisteredThreads;
   static TableTicker* sActiveSampler;