diff --git a/dom/media/VideoUtils.cpp b/dom/media/VideoUtils.cpp
index 08ee071691b8..088015bc064d 100644
--- a/dom/media/VideoUtils.cpp
+++ b/dom/media/VideoUtils.cpp
@@ -498,8 +498,8 @@ ParseCodecsString(const nsAString& aCodecs, nsTArray<nsString>& aOutCodecs)
 
 static bool
 CheckContentType(const nsAString& aContentType,
-                 mozilla::Function<bool(const nsAString&)> aSubtypeFilter,
-                 mozilla::Function<bool(const nsAString&)> aCodecFilter)
+                 mozilla::function<bool(const nsAString&)> aSubtypeFilter,
+                 mozilla::function<bool(const nsAString&)> aCodecFilter)
 {
   nsContentTypeParser parser(aContentType);
   nsAutoString mimeType;
diff --git a/gfx/2d/SFNTNameTable.h b/gfx/2d/SFNTNameTable.h
index f5e2ac31b9d1..3879e328d552 100644
--- a/gfx/2d/SFNTNameTable.h
+++ b/gfx/2d/SFNTNameTable.h
@@ -18,7 +18,7 @@ namespace gfx {
 struct NameHeader;
 struct NameRecord;
 
-typedef Vector<Function<bool(const NameRecord*)>> NameRecordMatchers;
+typedef Vector<function<bool(const NameRecord*)>> NameRecordMatchers;
 
 class SFNTNameTable final
 {
diff --git a/gfx/layers/apz/util/APZCCallbackHelper.h b/gfx/layers/apz/util/APZCCallbackHelper.h
index 93ff4f7309ae..ae6dd244bc7a 100644
--- a/gfx/layers/apz/util/APZCCallbackHelper.h
+++ b/gfx/layers/apz/util/APZCCallbackHelper.h
@@ -22,7 +22,7 @@ template<class T> class nsCOMPtr;
 namespace mozilla {
 namespace layers {
 
-typedef Function<void(uint64_t, const nsTArray<TouchBehaviorFlags>&)>
+typedef function<void(uint64_t, const nsTArray<TouchBehaviorFlags>&)>
         SetAllowedTouchBehaviorCallback;
 
 /* This class contains some helper methods that facilitate implementing the
diff --git a/gfx/layers/apz/util/APZEventState.h b/gfx/layers/apz/util/APZEventState.h
index 5572d5b1bee7..74936f040d00 100644
--- a/gfx/layers/apz/util/APZEventState.h
+++ b/gfx/layers/apz/util/APZEventState.h
@@ -28,7 +28,7 @@ namespace layers {
 
 class ActiveElementManager;
 
-typedef Function<void(const ScrollableLayerGuid&,
+typedef function<void(const ScrollableLayerGuid&,
                       uint64_t /* input block id */,
                       bool /* prevent default */)>
         ContentReceivedInputBlockCallback;
diff --git a/gfx/skia/skia/include/private/SkTLogic.h b/gfx/skia/skia/include/private/SkTLogic.h
index f94d13ecf8eb..5754d5d536fe 100644
--- a/gfx/skia/skia/include/private/SkTLogic.h
+++ b/gfx/skia/skia/include/private/SkTLogic.h
@@ -59,7 +59,11 @@ namespace std {
     #define false_type FalseType
     #define true_type TrueType
 
-    using mozilla::Function;
+    // If we have 'using mozilla::function', we're going to collide with
+    // 'std::function' on platforms that have it. Therefore we use a macro
+    // work around.
+    template<typename Signature>
+    using Function = mozilla::function<Signature>;
     #define function Function
 #endif
 }
diff --git a/mfbt/Function.h b/mfbt/Function.h
index 6a617e38314c..54278a4d0822 100644
--- a/mfbt/Function.h
+++ b/mfbt/Function.h
@@ -14,7 +14,7 @@
 #include "mozilla/RefCounted.h"
 #include "mozilla/RefPtr.h"
 
-// |Function<Signature>| is a wrapper that can hold any type of callable
+// |function<Signature>| is a wrapper that can hold any type of callable
 // object that can be invoked in a way that's compatible with |Signature|.
 // The standard "type erasure" technique is used to avoid the type of the
 // wrapper depending on the concrete type of the wrapped callable.
@@ -29,7 +29,7 @@
 // this is a function type; it's not used in any way other than serving as a
 // vehicle to encode the return and argument types into a single type.
 //
-// |Function| is default-constructible. A default-constructed instance is
+// |function| is default-constructible. A default-constructed instance is
 // considered "empty". Invoking an empty instance is undefined behaviour.
 // An empty instance can be populated with a callable by assigning to it.
 //
@@ -129,45 +129,45 @@ public:
 // and |Arguments| in the definition of the specialization without having to
 // introspect |Signature|.
 template<typename Signature>
-class Function;
+class function;
 
 template<typename ReturnType, typename... Arguments>
-class Function<ReturnType(Arguments...)>
+class function<ReturnType(Arguments...)>
 {
 public:
-  Function() {}
+  function() {}
 
   // This constructor is implicit to match the interface of |std::function|.
   template <typename Callable>
-  MOZ_IMPLICIT Function(const Callable& aCallable)
+  MOZ_IMPLICIT function(const Callable& aCallable)
     : mImpl(new detail::FunctionImpl<Callable, ReturnType, Arguments...>(aCallable))
   {}
-  MOZ_IMPLICIT Function(const Function& aFunction)
+  MOZ_IMPLICIT function(const function& aFunction)
     : mImpl(aFunction.mImpl)
   {}
-  MOZ_IMPLICIT Function(decltype(nullptr))
+  MOZ_IMPLICIT function(decltype(nullptr))
   {}
 
   // Move constructor and move assingment operator.
   // These should be generated automatically, but MSVC doesn't do that yet.
-  Function(Function&& aOther) : mImpl(Move(aOther.mImpl)) {}
-  Function& operator=(Function&& aOther) {
+  function(function&& aOther) : mImpl(Move(aOther.mImpl)) {}
+  function& operator=(function&& aOther) {
     mImpl = Move(aOther.mImpl);
     return *this;
   }
 
   template <typename Callable>
-  Function& operator=(const Callable& aCallable)
+  function& operator=(const Callable& aCallable)
   {
     mImpl = new detail::FunctionImpl<Callable, ReturnType, Arguments...>(aCallable);
     return *this;
   }
-  Function& operator=(const Function& aFunction)
+  function& operator=(const function& aFunction)
   {
     mImpl = aFunction.mImpl;
     return *this;
   }
-  Function& operator=(decltype(nullptr))
+  function& operator=(decltype(nullptr))
   {
     mImpl = nullptr;
     return *this;
diff --git a/mfbt/tests/TestFunction.cpp b/mfbt/tests/TestFunction.cpp
index 6074fab950a6..f9f36ce2788e 100644
--- a/mfbt/tests/TestFunction.cpp
+++ b/mfbt/tests/TestFunction.cpp
@@ -7,7 +7,7 @@
 #include "mozilla/Assertions.h"
 #include "mozilla/Function.h"
 
-using mozilla::Function;
+using mozilla::function;
 
 #define CHECK(c) \
   do { \
@@ -36,21 +36,21 @@ struct Incrementor {
 static void
 TestNonmemberFunction()
 {
-  Function<int(int)> f = &increment;
+  function<int(int)> f = &increment;
   CHECK(f(42) == 43);
 }
 
 static void
 TestStaticMemberFunction()
 {
-  Function<int(int)> f = &S::increment;
+  function<int(int)> f = &S::increment;
   CHECK(f(42) == 43);
 }
 
 static void
 TestFunctionObject()
 {
-  Function<int(int)> f = Incrementor();
+  function<int(int)> f = Incrementor();
   CHECK(f(42) == 43);
 }
 
@@ -58,19 +58,19 @@ static void
 TestLambda()
 {
   // Test non-capturing lambda
-  Function<int(int)> f = [](int arg){ return arg + 1; };
+  function<int(int)> f = [](int arg){ return arg + 1; };
   CHECK(f(42) == 43);
 
   // Test capturing lambda
   int one = 1;
-  Function<int(int)> g = [one](int arg){ return arg + one; };
+  function<int(int)> g = [one](int arg){ return arg + one; };
   CHECK(g(42) == 43);
 }
 
 static void
 TestDefaultConstructionAndAssignmentLater()
 {
-  Function<int(int)> f;  // allowed
+  function<int(int)> f;  // allowed
   // Would get an assertion if we tried calling f now.
   f = &increment;
   CHECK(f(42) == 43);
@@ -79,7 +79,7 @@ TestDefaultConstructionAndAssignmentLater()
 static void
 TestReassignment()
 {
-  Function<int(int)> f = &increment;
+  function<int(int)> f = &increment;
   CHECK(f(42) == 43);
   f = [](int arg){ return arg + 2; };
   CHECK(f(42) == 44);
@@ -88,7 +88,7 @@ TestReassignment()
 static void
 TestMemberFunction()
 {
-  Function<int(S&, int)> f = &S::decrement;
+  function<int(S&, int)> f = &S::decrement;
   S s;
   CHECK((f(s, 1) == 0));
 }
@@ -96,7 +96,7 @@ TestMemberFunction()
 static void
 TestConstMemberFunction()
 {
-  Function<int(const S*, int, int)> f = &S::sum;
+  function<int(const S*, int, int)> f = &S::sum;
   const S s;
   CHECK((f(&s, 1, 1) == 2));
 }
diff --git a/xpcom/base/NSPRLogModulesParser.cpp b/xpcom/base/NSPRLogModulesParser.cpp
index 43c80e915f46..31fe2587927e 100644
--- a/xpcom/base/NSPRLogModulesParser.cpp
+++ b/xpcom/base/NSPRLogModulesParser.cpp
@@ -15,7 +15,7 @@ namespace mozilla {
 
 void
 NSPRLogModulesParser(const char* aLogModules,
-                     Function<void(const char*, LogLevel)> aCallback)
+                     function<void(const char*, LogLevel)> aCallback)
 {
   if (!aLogModules) {
     return;
diff --git a/xpcom/base/NSPRLogModulesParser.h b/xpcom/base/NSPRLogModulesParser.h
index 664bd73e68a9..5ecafe13ed91 100644
--- a/xpcom/base/NSPRLogModulesParser.h
+++ b/xpcom/base/NSPRLogModulesParser.h
@@ -17,6 +17,6 @@ namespace mozilla {
  * @param aCallback The callback to invoke for each log module config entry.
  */
 void NSPRLogModulesParser(const char* aLogModules,
-                          Function<void(const char*, LogLevel)> aCallback);
+                          function<void(const char*, LogLevel)> aCallback);
 
 } // namespace mozilla