diff --git a/src/MacVim/MMAppController.m b/src/MacVim/MMAppController.m
index f242b61042..6f15abafb7 100644
--- a/src/MacVim/MMAppController.m
+++ b/src/MacVim/MMAppController.m
@@ -185,6 +185,10 @@ fsEventCallback(ConstFSEventStreamRef streamRef,
         [NSNumber numberWithBool:NO],   MMVerticalSplitKey,
         [NSNumber numberWithInt:0],     MMPreloadCacheSizeKey,
         [NSNumber numberWithInt:0],     MMLastWindowClosedBehaviorKey,
+        [NSNumber numberWithInt:MMDisableFakeEsc],
+                                        MMFakeEscModifierKey,
+        [NSNumber numberWithFloat:0.3], MMFakeEscTimeoutKey,
+        [NSNumber numberWithBool:NO],   MMFakeEscOnKeyDownKey,
         nil];
 
     [[NSUserDefaults standardUserDefaults] registerDefaults:dict];
diff --git a/src/MacVim/MMApplication.h b/src/MacVim/MMApplication.h
index 28937e9745..a03c2c655c 100644
--- a/src/MacVim/MMApplication.h
+++ b/src/MacVim/MMApplication.h
@@ -12,6 +12,13 @@
 
 
 @interface MMApplication : NSApplication {
+    CFAbsoluteTime  fakeEscTimeDown;
+    CFAbsoluteTime  fakeEscTimeout;
+    int             fakeEscKeyCode;
+    unsigned        fakeEscModifierMask;
+    BOOL            blockFakeEscEvent;
+    BOOL            blockKeyDown;
+    BOOL            fakeEscOnKeyDown;
 }
 
 @end
diff --git a/src/MacVim/MMApplication.m b/src/MacVim/MMApplication.m
index 10c69d9d62..55bcae0175 100644
--- a/src/MacVim/MMApplication.m
+++ b/src/MacVim/MMApplication.m
@@ -14,6 +14,7 @@
  */
 
 #import "MMApplication.h"
+#import "Miscellaneous.h"
 
 // Ctrl-Tab is broken on pre 10.5, so we add a hack to make it work.
 #if MAC_OS_X_VERSION_MAX_ALLOWED <= MAC_OS_X_VERSION_10_4
@@ -26,11 +27,107 @@
 
 @implementation MMApplication
 
+- (void)awakeFromNib
+{
+    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
+    switch ([ud integerForKey:MMFakeEscModifierKey]) {
+    case MMCtrlFakeEsc:
+        fakeEscKeyCode = 59;
+        fakeEscModifierMask = NSControlKeyMask;
+        break;
+    case MMAltFakeEsc:
+        fakeEscKeyCode = 58;
+        fakeEscModifierMask = NSAlternateKeyMask;
+        break;
+    case MMCmdFakeEsc:
+        fakeEscKeyCode = 55;
+        fakeEscModifierMask = NSCommandKeyMask;
+        break;
+    default:
+        fakeEscKeyCode = fakeEscModifierMask = 0;
+    }
+
+    fakeEscTimeout = [ud floatForKey:MMFakeEscTimeoutKey];
+    fakeEscOnKeyDown = [ud boolForKey:MMFakeEscOnKeyDownKey];
+}
+
 - (void)sendEvent:(NSEvent *)event
 {
     NSEventType type = [event type];
     unsigned flags = [event modifierFlags];
 
+    // The following hack allows the user to set one modifier key of choice
+    // (Ctrl, Alt, or Cmd) to generate an Esc key press event.  In order for
+    // the key to still be used as a modifier we only send the "faked" Esc
+    // event if the modifier was pressed and released without any other keys
+    // being pressed in between.  The user may elect to have the chosen
+    // modifier sending Esc on key down, since sending it on key up makes it
+    // appear a bit sluggish.  However, this effectively disables the modifier
+    // key (but only the left key and not the right one, in case there are two
+    // on the keyboard).
+    //
+    // This hack is particularly useful in conjunction with Mac OS X's ability
+    // to turn Caps-Lock into a modifier key of choice because it enables us to
+    // turn Caps-Lock into a quasi-Esc key!  (This remapping be done inside
+    // "System Preferences -> Keyboard & Mouse -> Modifier Keys...".)
+    //
+    if (fakeEscKeyCode != 0) {
+        if (NSFlagsChanged == type && [event keyCode] == fakeEscKeyCode) {
+            BOOL sendEsc = NO;
+            CFAbsoluteTime timeNow = CFAbsoluteTimeGetCurrent();
+
+            if ((flags & fakeEscModifierMask) == 0) {
+                // The chosen modifier was released.  If the modifier was
+                // recently pressed then convert this event to a "fake" Esc key
+                // press event.
+                if (!blockFakeEscEvent && !fakeEscOnKeyDown &&
+                        timeNow - fakeEscTimeDown < fakeEscTimeout)
+                    sendEsc = YES;
+
+                blockFakeEscEvent = YES;
+                blockKeyDown = NO;
+            } else {
+                // The chosen modifier was pressed.
+                blockFakeEscEvent = NO;
+                fakeEscTimeDown = timeNow;
+
+                if (fakeEscOnKeyDown) {
+                    sendEsc = YES;
+
+                    // Block key down while the fake Esc modifier key is held,
+                    // otherwise "marked text" may pop up if a key is pressed
+                    // while the fake Esc modifier is held (which looks ugly,
+                    // but is harmless).
+                    blockKeyDown = YES;
+                }
+            }
+
+            if (sendEsc) {
+                NSEvent *e = [NSEvent keyEventWithType:NSKeyDown
+                                         location:[event locationInWindow]
+                                    modifierFlags:flags & 0x0000ffffU
+                                        timestamp:[event timestamp]
+                                     windowNumber:[event windowNumber]
+                                          context:[event context]
+                                       characters:@"\x1b"   // Esc
+                      charactersIgnoringModifiers:@"\x1b"
+                                        isARepeat:NO
+                                          keyCode:53];
+
+                [self postEvent:e atStart:YES];
+                return;
+            }
+        } else if (type != NSKeyUp) {
+            // Another event occurred, so don't send any fake Esc events now
+            // (else the modifier would not function as a modifier key any
+            // more).
+            blockFakeEscEvent = YES;
+        }
+
+        if (blockKeyDown && type == NSKeyDown)
+            return;
+    }
+
 #ifdef MM_CTRL_TAB_HACK
     NSResponder *firstResponder = [[self keyWindow] firstResponder];
 
@@ -51,7 +148,7 @@
     // key event.
     if ((NSKeyDown == type || NSKeyUp == type) && (flags & NSHelpKeyMask)) {
         flags &= ~NSHelpKeyMask;
-        event = [NSEvent keyEventWithType:[event type]
+        NSEvent *e = [NSEvent keyEventWithType:[event type]
                                  location:[event locationInWindow]
                             modifierFlags:flags
                                 timestamp:[event timestamp]
@@ -61,6 +158,9 @@
               charactersIgnoringModifiers:[event charactersIgnoringModifiers]
                                 isARepeat:[event isARepeat]
                                   keyCode:[event keyCode]];
+
+        [self postEvent:e atStart:YES];
+        return;
     }
 
     [super sendEvent:event];
diff --git a/src/MacVim/Miscellaneous.h b/src/MacVim/Miscellaneous.h
index 23c3ebe206..ce4a02b55f 100644
--- a/src/MacVim/Miscellaneous.h
+++ b/src/MacVim/Miscellaneous.h
@@ -53,6 +53,9 @@ extern NSString *MMOpenLayoutKey;
 extern NSString *MMVerticalSplitKey;
 extern NSString *MMPreloadCacheSizeKey;
 extern NSString *MMLastWindowClosedBehaviorKey;
+extern NSString *MMFakeEscModifierKey;
+extern NSString *MMFakeEscTimeoutKey;
+extern NSString *MMFakeEscOnKeyDownKey;
 
 
 // Enum for MMUntitledWindowKey
@@ -79,6 +82,14 @@ enum {
     MMTerminateWhenLastWindowClosed = 2,
 };
 
+// Enum for MMFakeEscModifierKey
+enum {
+    MMDisableFakeEsc    = 0,
+    MMCtrlFakeEsc       = 1,
+    MMAltFakeEsc        = 2,
+    MMCmdFakeEsc        = 3
+};
+
 
 
 
diff --git a/src/MacVim/Miscellaneous.m b/src/MacVim/Miscellaneous.m
index 15259d48d7..f36050357a 100644
--- a/src/MacVim/Miscellaneous.m
+++ b/src/MacVim/Miscellaneous.m
@@ -44,6 +44,9 @@ NSString *MMOpenLayoutKey               = @"MMOpenLayout";
 NSString *MMVerticalSplitKey            = @"MMVerticalSplit";
 NSString *MMPreloadCacheSizeKey         = @"MMPreloadCacheSize";
 NSString *MMLastWindowClosedBehaviorKey = @"MMLastWindowClosedBehavior";
+NSString *MMFakeEscModifierKey          = @"MMFakeEscModifier";
+NSString *MMFakeEscTimeoutKey           = @"MMFakeEscTimeout";
+NSString *MMFakeEscOnKeyDownKey         = @"MMFakeEscOnKeyDown";