diff --git a/atom/browser/native_window_views.cc b/atom/browser/native_window_views.cc
index dc1d684ea2b6..9a7e6d528be0 100644
--- a/atom/browser/native_window_views.cc
+++ b/atom/browser/native_window_views.cc
@@ -113,9 +113,12 @@ bool IsAltKey(const content::NativeWebKeyboardEvent& event) {
 
 bool IsAltModifier(const content::NativeWebKeyboardEvent& event) {
   typedef content::NativeWebKeyboardEvent::Modifiers Modifiers;
-  return (event.modifiers == Modifiers::AltKey) ||
-         (event.modifiers == (Modifiers::AltKey | Modifiers::IsLeft)) ||
-         (event.modifiers == (Modifiers::AltKey | Modifiers::IsRight));
+  int modifiers = event.modifiers;
+  modifiers &= ~Modifiers::NumLockOn;
+  modifiers &= ~Modifiers::CapsLockOn;
+  return (modifiers == Modifiers::AltKey) ||
+         (modifiers == (Modifiers::AltKey | Modifiers::IsLeft)) ||
+         (modifiers == (Modifiers::AltKey | Modifiers::IsRight));
 }
 
 class NativeWindowClientView : public views::ClientView {