diff --git a/key.go b/key.go
index 7e99b6f..170ef39 100644
--- a/key.go
+++ b/key.go
@@ -372,19 +372,21 @@ func checkKeyCodes(k string) (key C.MMKeyCode, err error) {
 
 func checkKeyFlags(f string) (flags C.MMKeyFlags) {
 	m := map[string]C.MMKeyFlags{
-		"alt":    C.MOD_ALT,
-		"ralt":   C.MOD_ALT,
-		"lalt":   C.MOD_ALT,
-		"cmd":    C.MOD_META,
-		"rcmd":   C.MOD_META,
-		"lcmd":   C.MOD_META,
-		"ctrl":   C.MOD_CONTROL,
-		"rctrl":  C.MOD_CONTROL,
-		"lctrl":  C.MOD_CONTROL,
-		"shift":  C.MOD_SHIFT,
-		"rshift": C.MOD_SHIFT,
-		"lshift": C.MOD_SHIFT,
-		"none":   C.MOD_NONE,
+		"alt":     C.MOD_ALT,
+		"ralt":    C.MOD_ALT,
+		"lalt":    C.MOD_ALT,
+		"cmd":     C.MOD_META,
+		"command": C.MOD_META,
+		"rcmd":    C.MOD_META,
+		"lcmd":    C.MOD_META,
+		"ctrl":    C.MOD_CONTROL,
+		"control": C.MOD_CONTROL,
+		"rctrl":   C.MOD_CONTROL,
+		"lctrl":   C.MOD_CONTROL,
+		"shift":   C.MOD_SHIFT,
+		"rshift":  C.MOD_SHIFT,
+		"lshift":  C.MOD_SHIFT,
+		"none":    C.MOD_NONE,
 	}
 
 	if v, ok := m[f]; ok {
@@ -408,6 +410,51 @@ func getFlagsFromValue(value []string) (flags C.MMKeyFlags) {
 	return
 }
 
+func modifierFlagForKeyName(key string) (C.MMKeyFlags, bool) {
+	flag := checkKeyFlags(key)
+	return flag, flag != C.MOD_NONE
+}
+
+func modifierKeyEventDownDarwin(keyArr []string, pid int) C.MMKeyFlags {
+	var active C.MMKeyFlags
+
+	for _, key := range keyArr {
+		flag, ok := modifierFlagForKeyName(key)
+		if !ok {
+			continue
+		}
+
+		keyCode, err := checkKeyCodes(key)
+		if err != nil {
+			continue
+		}
+
+		active |= flag
+		C.toggleKeyCode(keyCode, true, active, C.uintptr(pid))
+		MilliSleep(1)
+	}
+
+	return active
+}
+
+func modifierKeyEventUpDarwin(keyArr []string, pid int, active C.MMKeyFlags) {
+	for i := len(keyArr) - 1; i >= 0; i-- {
+		flag, ok := modifierFlagForKeyName(keyArr[i])
+		if !ok {
+			continue
+		}
+
+		keyCode, err := checkKeyCodes(keyArr[i])
+		if err != nil {
+			continue
+		}
+
+		active &^= flag
+		C.toggleKeyCode(keyCode, false, active, C.uintptr(pid))
+		MilliSleep(1)
+	}
+}
+
 func upKeyArr(keyArr []string, pid int) {
 	for i := 0; i < len(keyArr); i++ {
 		key1, _ := checkKeyCodes(keyArr[i])
@@ -422,6 +469,14 @@ func keyTaps(k string, keyArr []string, pid int) error {
 		return err
 	}
 
+	if runtime.GOOS == "darwin" && len(keyArr) > 0 {
+		active := modifierKeyEventDownDarwin(keyArr, pid)
+		tapKeyCode(key, active, C.uintptr(pid))
+		MilliSleep(KeySleep)
+		modifierKeyEventUpDarwin(keyArr, pid, active)
+		return nil
+	}
+
 	tapKeyCode(key, flags, C.uintptr(pid))
 	MilliSleep(KeySleep)
 	upKeyArr(keyArr, pid)
@@ -451,6 +506,20 @@ func keyTogglesB(k string, down bool, keyArr []string, pid int) error {
 		return err
 	}
 
+	if runtime.GOOS == "darwin" && len(keyArr) > 0 {
+		if down {
+			active := modifierKeyEventDownDarwin(keyArr, pid)
+			C.toggleKeyCode(key, C.bool(down), active, C.uintptr(pid))
+			MilliSleep(KeySleep)
+			return nil
+		}
+
+		C.toggleKeyCode(key, C.bool(down), flags, C.uintptr(pid))
+		MilliSleep(KeySleep)
+		modifierKeyEventUpDarwin(keyArr, pid, flags)
+		return nil
+	}
+
 	C.toggleKeyCode(key, C.bool(down), flags, C.uintptr(pid))
 	MilliSleep(KeySleep)
 	if !down {
diff --git a/key/keypress_c.h b/key/keypress_c.h
index b93eeaf..49f7473 100644
--- a/key/keypress_c.h
+++ b/key/keypress_c.h
@@ -66,6 +66,29 @@
 		return 0;
 	}
 
+	static CGEventSourceRef CreateKeyboardEventSource(void) {
+		return CGEventSourceCreate(kCGEventSourceStateCombinedSessionState);
+	}
+
+	static CGEventFlags modifierFlagForKeyCode(MMKeyCode code) {
+		if (code == K_META || code == K_LMETA || code == K_RMETA) {
+			return kCGEventFlagMaskCommand;
+		}
+		if (code == K_ALT || code == K_LALT || code == K_RALT) {
+			return kCGEventFlagMaskAlternate;
+		}
+		if (code == K_CONTROL || code == K_LCONTROL || code == K_RCONTROL) {
+			return kCGEventFlagMaskControl;
+		}
+		if (code == K_SHIFT || code == K_LSHIFT || code == K_RSHIFT) {
+			return kCGEventFlagMaskShift;
+		}
+		if (code == K_CAPSLOCK) {
+			return kCGEventFlagMaskAlphaShift;
+		}
+		return 0;
+	}
+
 	static io_connect_t _getAuxiliaryKeyDriver(void) {
 		static mach_port_t sEventDrvrRef = 0;
 		mach_port_t masterPort, service, iter;
@@ -176,19 +199,27 @@ void toggleKeyCode(MMKeyCode code, const bool down, MMKeyFlags flags, uintptr pi
 		event.compound.subType = NX_SUBTYPE_AUX_CONTROL_BUTTONS;
 		event.compound.misc.L[0] = evtInfo;
 
-		kr = IOHIDPostEvent(_getAuxiliaryKeyDriver(), 
+		kr = IOHIDPostEvent(_getAuxiliaryKeyDriver(),
 								NX_SYSDEFINED, loc, &event, kNXEventDataVersion, 0, FALSE);
 		assert(KERN_SUCCESS == kr);
 	} else {
-		CGEventSourceRef source = CGEventSourceCreate(kCGEventSourceStateHIDSystemState);
+		CGEventFlags modifierFlag = modifierFlagForKeyCode(code);
+		CGEventFlags eventFlags = (CGEventFlags)flags;
+		CGEventType eventType = down ? kCGEventKeyDown : kCGEventKeyUp;
+		if (modifierFlag != 0) {
+			eventType = kCGEventFlagsChanged;
+			if (eventFlags == 0 && down) {
+				eventFlags = modifierFlag;
+			}
+		}
+
+		CGEventSourceRef source = CreateKeyboardEventSource();
 		CGEventRef keyEvent = CGEventCreateKeyboardEvent(source, (CGKeyCode)code, down);
 		assert(keyEvent != NULL);
 
-		CGEventSetType(keyEvent, down ? kCGEventKeyDown : kCGEventKeyUp);
-		if (flags != 0) {
-			CGEventSetFlags(keyEvent, (CGEventFlags) flags);
-		}
-		
+		CGEventSetType(keyEvent, eventType);
+		CGEventSetFlags(keyEvent, eventFlags);
+
 		SendTo(pid, keyEvent);
 		CFRelease(source);
 	}
@@ -276,7 +307,7 @@ void toggleKey(char c, const bool down, MMKeyFlags flags, uintptr pid) {
 		convert characters to a keycode, but does not support adding modifier flags. 
 		It is only used in typeString().
 		-- if you need modifier keys, use the above functions instead. */
-		CGEventSourceRef source = CGEventSourceCreate(kCGEventSourceStateHIDSystemState);
+		CGEventSourceRef source = CreateKeyboardEventSource();
 		CGEventRef keyEvent = CGEventCreateKeyboardEvent(source, 0, down);
 		if (keyEvent == NULL) {
 			fputs("Could not create keyboard event.\n", stderr);
@@ -357,4 +388,4 @@ void unicodeType(const unsigned value, uintptr pid, int8_t isPid) {
 	int input_utf(const char *utf){
 		return 0;
 	}
-#endif
\ No newline at end of file
+#endif