diff --git a/dom/bluetooth/bluedroid/BluetoothAvrcpManager.cpp b/dom/bluetooth/bluedroid/BluetoothAvrcpManager.cpp
index cca192d74365..082247e6bd11 100644
--- a/dom/bluetooth/bluedroid/BluetoothAvrcpManager.cpp
+++ b/dom/bluetooth/bluedroid/BluetoothAvrcpManager.cpp
@@ -442,7 +442,7 @@ public:
   {
     MOZ_ASSERT(mManager);
   }
-  NS_METHOD Run() override
+  NS_IMETHOD Run() override
   {
     mManager->OnConnect(EmptyString());
     return NS_OK;
@@ -475,7 +475,7 @@ public:
   {
     MOZ_ASSERT(mManager);
   }
-  NS_METHOD Run() override
+  NS_IMETHOD Run() override
   {
     mManager->OnDisconnect(EmptyString());
     return NS_OK;
diff --git a/dom/media/MediaRecorder.cpp b/dom/media/MediaRecorder.cpp
index dc82bb3112c4..b029245499b9 100644
--- a/dom/media/MediaRecorder.cpp
+++ b/dom/media/MediaRecorder.cpp
@@ -73,7 +73,7 @@ public:
     }
   }
 
-  NS_METHOD
+  NS_IMETHOD
   CollectReports(nsIHandleReportCallback* aHandleReport,
                  nsISupports* aData, bool aAnonymize) override
   {
diff --git a/layout/generic/nsPluginFrame.h b/layout/generic/nsPluginFrame.h
index 92509c95b593..2da863ab1f05 100644
--- a/layout/generic/nsPluginFrame.h
+++ b/layout/generic/nsPluginFrame.h
@@ -105,7 +105,7 @@ public:
 
   virtual void DidSetStyleContext(nsStyleContext* aOldStyleContext) override;
 
-  NS_METHOD GetPluginInstance(nsNPAPIPluginInstance** aPluginInstance) override;
+  NS_IMETHOD GetPluginInstance(nsNPAPIPluginInstance** aPluginInstance) override;
 
   virtual void SetIsDocumentActive(bool aIsActive) override;
 
diff --git a/toolkit/components/osfile/NativeOSFileInternals.cpp b/toolkit/components/osfile/NativeOSFileInternals.cpp
index c3317bddc6c2..e4725d390de9 100644
--- a/toolkit/components/osfile/NativeOSFileInternals.cpp
+++ b/toolkit/components/osfile/NativeOSFileInternals.cpp
@@ -594,7 +594,7 @@ public:
     MOZ_ASSERT(NS_IsMainThread());
   }
 
-  NS_METHOD Run() override {
+  NS_IMETHOD Run() override {
     MOZ_ASSERT(!NS_IsMainThread());
     TimeStamp dispatchDate = TimeStamp::Now();
 
diff --git a/toolkit/crashreporter/nsExceptionHandler.cpp b/toolkit/crashreporter/nsExceptionHandler.cpp
index a41928d22473..f1f801dca61f 100644
--- a/toolkit/crashreporter/nsExceptionHandler.cpp
+++ b/toolkit/crashreporter/nsExceptionHandler.cpp
@@ -2126,7 +2126,7 @@ public:
     , mAppendAppNotes(true)
     {}
 
-  NS_METHOD Run() override;
+  NS_IMETHOD Run() override;
 
 private:
   nsCString mKey;
diff --git a/widget/nsDeviceContextSpecProxy.h b/widget/nsDeviceContextSpecProxy.h
index 6997c80a3da2..aea5f985fbc0 100644
--- a/widget/nsDeviceContextSpecProxy.h
+++ b/widget/nsDeviceContextSpecProxy.h
@@ -27,28 +27,28 @@ class nsDeviceContextSpecProxy final : public nsIDeviceContextSpec
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD Init(nsIWidget* aWidget, nsIPrintSettings* aPrintSettings,
+  NS_IMETHOD Init(nsIWidget* aWidget, nsIPrintSettings* aPrintSettings,
                  bool aIsPrintPreview) final;
 
   virtual already_AddRefed<PrintTarget> MakePrintTarget() final;
 
-  NS_METHOD GetDrawEventRecorder(mozilla::gfx::DrawEventRecorder** aDrawEventRecorder) final;
+  NS_IMETHOD GetDrawEventRecorder(mozilla::gfx::DrawEventRecorder** aDrawEventRecorder) final;
 
   float GetDPI() final;
 
   float GetPrintingScale() final;
 
-  NS_METHOD BeginDocument(const nsAString& aTitle,
-                          const nsAString& aPrintToFileName,
-                          int32_t aStartPage, int32_t aEndPage) final;
+  NS_IMETHOD BeginDocument(const nsAString& aTitle,
+                           const nsAString& aPrintToFileName,
+                           int32_t aStartPage, int32_t aEndPage) final;
 
-  NS_METHOD EndDocument() final;
+  NS_IMETHOD EndDocument() final;
 
-  NS_METHOD AbortDocument() final;
+  NS_IMETHOD AbortDocument() final;
 
-  NS_METHOD BeginPage() final;
+  NS_IMETHOD BeginPage() final;
 
-  NS_METHOD EndPage() final;
+  NS_IMETHOD EndPage() final;
 
 private:
   ~nsDeviceContextSpecProxy() {}
diff --git a/xpcom/base/nsMemoryReporterManager.cpp b/xpcom/base/nsMemoryReporterManager.cpp
index 0079976dbc19..9fc85ebc44e6 100644
--- a/xpcom/base/nsMemoryReporterManager.cpp
+++ b/xpcom/base/nsMemoryReporterManager.cpp
@@ -804,8 +804,8 @@ class WindowsAddressSpaceReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     // First iterate over all the segments and record how many of each kind
     // there were and their aggregate sizes. We use a hash table for this
@@ -987,8 +987,8 @@ class VsizeMaxContiguousReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     int64_t amount;
     nsresult rv = VsizeMaxContiguousDistinguishedAmount(&amount);
@@ -1010,8 +1010,8 @@ class PrivateReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     int64_t amount;
     nsresult rv = PrivateDistinguishedAmount(&amount);
@@ -1034,8 +1034,8 @@ class VsizeReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     int64_t amount;
     nsresult rv = VsizeDistinguishedAmount(&amount);
@@ -1061,8 +1061,8 @@ class ResidentReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     int64_t amount;
     nsresult rv = ResidentDistinguishedAmount(&amount);
@@ -1090,8 +1090,8 @@ class ResidentUniqueReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     int64_t amount = 0;
     nsresult rv = ResidentUniqueDistinguishedAmount(&amount);
@@ -1118,8 +1118,8 @@ class SystemHeapReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     int64_t amount;
     nsresult rv = SystemHeapSize(&amount);
@@ -1174,8 +1174,8 @@ class ResidentPeakReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     int64_t amount = 0;
     nsresult rv = ResidentPeakDistinguishedAmount(&amount);
@@ -1197,8 +1197,8 @@ class PageFaultsSoftReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     struct rusage usage;
     int err = getrusage(RUSAGE_SELF, &usage);
@@ -1241,8 +1241,8 @@ class PageFaultsHardReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     int64_t amount = 0;
     nsresult rv = PageFaultsHardDistinguishedAmount(&amount);
@@ -1298,8 +1298,8 @@ class JemallocHeapReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     jemalloc_stats_t stats;
     jemalloc_stats(&stats);
@@ -1392,8 +1392,8 @@ class AtomTablesReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     size_t Main, Static;
     NS_SizeOfAtomTablesIncludingThis(MallocSizeOf, &Main, &Static);
@@ -1429,8 +1429,8 @@ class DeadlockDetectorReporter final : public nsIMemoryReporter
 public:
   NS_DECL_ISUPPORTS
 
-  NS_METHOD CollectReports(nsIHandleReportCallback* aHandleReport,
-                           nsISupports* aData, bool aAnonymize) override
+  NS_IMETHOD CollectReports(nsIHandleReportCallback* aHandleReport,
+                            nsISupports* aData, bool aAnonymize) override
   {
     return MOZ_COLLECT_REPORT(
       "explicit/deadlock-detector", KIND_HEAP, UNITS_BYTES,
diff --git a/xpcom/threads/TaskQueue.h b/xpcom/threads/TaskQueue.h
index 6f40cfe3fcfa..19f5c942d2eb 100644
--- a/xpcom/threads/TaskQueue.h
+++ b/xpcom/threads/TaskQueue.h
@@ -173,7 +173,7 @@ protected:
       : mQueue(aQueue)
     {
     }
-    NS_METHOD Run() override;
+    NS_IMETHOD Run() override;
   private:
     RefPtr<TaskQueue> mQueue;
   };