diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7c072fed..55af39fb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,8 @@
 - On X11, the environment variable `WINIT_HIDPI_FACTOR` has been added for overriding DPI factor.
 - On X11, enabling transparency no longer causes the window contents to flicker when resizing.
 - On X11, `with_override_redirect` now actually enables override redirect.
+- macOS now generates `VirtualKeyCode::LAlt` and `VirtualKeyCode::RAlt` instead of `None` for both.
+- On macOS, `VirtualKeyCode::RWin` and `VirtualKeyCode::LWin` are no longer switched.
 
 # Version 0.15.0 (2018-05-22)
 
diff --git a/src/platform/macos/events_loop.rs b/src/platform/macos/events_loop.rs
index 22c349dd..6b6d1c67 100644
--- a/src/platform/macos/events_loop.rs
+++ b/src/platform/macos/events_loop.rs
@@ -598,14 +598,14 @@ pub fn to_virtual_key_code(code: c_ushort) -> Option<events::VirtualKeyCode> {
         0x33 => events::VirtualKeyCode::Back,
         //0x34 => unkown,
         0x35 => events::VirtualKeyCode::Escape,
-        0x36 => events::VirtualKeyCode::RWin,
-        0x37 => events::VirtualKeyCode::LWin,
+        0x36 => events::VirtualKeyCode::LWin,
+        0x37 => events::VirtualKeyCode::RWin,
         0x38 => events::VirtualKeyCode::LShift,
         //0x39 => Caps lock,
-        //0x3a => Left alt,
+        0x3a => events::VirtualKeyCode::LAlt,
         0x3b => events::VirtualKeyCode::LControl,
         0x3c => events::VirtualKeyCode::RShift,
-        //0x3d => Right alt,
+        0x3d => events::VirtualKeyCode::RAlt,
         0x3e => events::VirtualKeyCode::RControl,
         //0x3f => Fn key,
         //0x40 => F17 Key,
@@ -695,7 +695,7 @@ unsafe fn modifier_event(
     keymask: NSEventModifierFlags,
     key_pressed: bool,
 ) -> Option<WindowEvent> {
-    if !key_pressed && NSEvent::modifierFlags(ns_event).contains(keymask) 
+    if !key_pressed && NSEvent::modifierFlags(ns_event).contains(keymask)
     || key_pressed && !NSEvent::modifierFlags(ns_event).contains(keymask) {
         let state = ElementState::Released;
         let keycode = NSEvent::keyCode(ns_event);