diff --git a/src/MacVim/MMBackend.h b/src/MacVim/MMBackend.h
index e8271f2ded..93c3cdb997 100644
--- a/src/MacVim/MMBackend.h
+++ b/src/MacVim/MMBackend.h
@@ -57,6 +57,8 @@
 #endif
 }
 
+@property (nonatomic, readonly) NSSize cellSize;
+
 + (MMBackend *)sharedInstance;
 
 - (void)setBackgroundColor:(int)color;
diff --git a/src/MacVim/MMBackend.m b/src/MacVim/MMBackend.m
index 21ade18abb..87b2d6b9f7 100644
--- a/src/MacVim/MMBackend.m
+++ b/src/MacVim/MMBackend.m
@@ -171,6 +171,7 @@ - (void)focusChange:(BOOL)on;
 - (void)handleToggleToolbar;
 - (void)handleScrollbarEvent:(NSData *)data;
 - (void)handleSetFont:(NSData *)data;
+- (void)handleCellSize:(NSData *)data;
 - (void)handleDropFiles:(NSData *)data;
 - (void)handleDropString:(NSData *)data;
 - (void)startOdbEditWithArguments:(NSDictionary *)args;
@@ -1328,6 +1329,9 @@ - (oneway void)processInput:(int)msgid data:(in bycopy NSData *)data
         // modified files when we get here.
         isTerminating = YES;
         getout(0);
+    } else if (UpdateCellSizeMsgID == msgid) {
+        // Immediately handle simple state updates to they can be reflected in Vim.
+        [self handleCellSize:data];
     } else {
         // First remove previous instances of this message from the input
         // queue, else the input queue may fill up as a result of Vim not being
@@ -2705,6 +2709,18 @@ - (void)handleSetFont:(NSData *)data
     CONVERT_FROM_UTF8_FREE(s);
 }
 
+- (void)handleCellSize:(NSData *)data
+{
+    if (!data) return;
+
+    const void *bytes = [data bytes];
+
+    // Don't use gui.char_width/height because for simplicity we set those to
+    // 1. We store the cell size separately (it's only used for
+    // getcellpixels()).
+    memcpy(&_cellSize, bytes, sizeof(NSSize));
+}
+
 - (void)handleDropFiles:(NSData *)data
 {
     // TODO: Get rid of this method; instead use Vim script directly.  At the
diff --git a/src/MacVim/MMVimController.m b/src/MacVim/MMVimController.m
index 4d0a295722..05eb56f11a 100644
--- a/src/MacVim/MMVimController.m
+++ b/src/MacVim/MMVimController.m
@@ -1012,6 +1012,14 @@ - (void)handleMessage:(int)msgid data:(NSData *)data
             }
 
             [windowController setFont:font];
+
+            // Notify Vim of updated cell size for getcellpixels(). Note that
+            // this is asynchronous, which means getcellpixels() will not be
+            // immediately reflected after setting guifont.
+            NSSize cellsize = windowController.vimView.textView.cellSize;
+            [self sendMessage:UpdateCellSizeMsgID
+                         data:[NSData dataWithBytes:&cellsize length:sizeof(cellsize)]];
+
             [name release];
         }
         break;
diff --git a/src/MacVim/MacVim.h b/src/MacVim/MacVim.h
index 3d2b17425f..46dbd2b0ea 100644
--- a/src/MacVim/MacVim.h
+++ b/src/MacVim/MacVim.h
@@ -300,6 +300,7 @@ extern const char * const MMVimMsgIDStrings[];
     MSG(ScrollbarEventMsgID) \
     MSG(SetFontMsgID) \
     MSG(SetWideFontMsgID) \
+    MSG(UpdateCellSizeMsgID) \
     MSG(VimShouldCloseMsgID) \
     MSG(SetDefaultColorsMsgID) \
     MSG(SetTablineColorsMsgID) \
diff --git a/src/MacVim/gui_macvim.m b/src/MacVim/gui_macvim.m
index 7ea4212c11..2526f37b64 100644
--- a/src/MacVim/gui_macvim.m
+++ b/src/MacVim/gui_macvim.m
@@ -247,6 +247,9 @@
     // correspondence (assuming all characters have the same dimensions).
     gui.scrollbar_width = gui.scrollbar_height = 0;
 
+    // For simplicity we just set char width/height to 1 as the GUI is
+    // decoupled from Vim anyway so Vim doesn't need to know the accurate
+    // pixel sizes.
     gui.char_height = 1;
     gui.char_width = 1;
     gui.char_ascent = 0;
@@ -1664,6 +1667,14 @@
     return OK;
 }
 
+    void
+gui_mch_calc_cell_size(struct cellsize *cs_out)
+{
+    NSSize cellsize = [MMBackend sharedInstance].cellSize;
+    cs_out->cs_xpixel = round(cellsize.width);
+    cs_out->cs_ypixel = round(cellsize.height);
+}
+
 
     void
 gui_mch_beep(void)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 43e56767cb..0312218274 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -5425,8 +5425,15 @@ f_getcellpixels(typval_T *argvars UNUSED, typval_T *rettv)
     if (gui.in_use)
     {
         // success pixel size and no gui.
+#ifdef FEAT_GUI_MACVIM
+        struct cellsize cs;
+        gui_mch_calc_cell_size(&cs);
+        list_append_number(rettv->vval.v_list, (varnumber_T)cs.cs_xpixel);
+        list_append_number(rettv->vval.v_list, (varnumber_T)cs.cs_ypixel);
+#else
         list_append_number(rettv->vval.v_list, (varnumber_T)gui.char_width);
         list_append_number(rettv->vval.v_list, (varnumber_T)gui.char_height);
+#endif
     }
     else
 #endif
diff --git a/src/os_unix.c b/src/os_unix.c
index bf82fd81d3..790f8281ed 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -4442,7 +4442,16 @@ mch_report_winsize(int fd, int rows, int cols)
 
     // calcurate and set tty pixel size
     struct cellsize cs;
-    mch_calc_cell_size(&cs);
+#if defined(FEAT_GUI) && defined(FEAT_GUI_MACVIM)
+    if (gui.in_use)
+    {
+	gui_mch_calc_cell_size(&cs);
+    }
+    else
+#endif
+    {
+	mch_calc_cell_size(&cs);
+    }
 
     if (cs.cs_xpixel == -1)
     {
diff --git a/src/proto/gui_macvim.pro b/src/proto/gui_macvim.pro
index 7d27521d5d..eaa46b200f 100644
--- a/src/proto/gui_macvim.pro
+++ b/src/proto/gui_macvim.pro
@@ -43,6 +43,7 @@ void gui_mch_set_font(GuiFont font);
 void gui_mch_expand_font(optexpand_T *args, void *param, int (*add_match)(char_u *val));
 int gui_mch_adjust_charheight(void);
 int gui_mch_adjust_charwidth(void);
+void gui_mch_calc_cell_size(struct cellsize *cs_out);
 void gui_mch_beep(void);
 char_u *gui_mch_browse(int saving, char_u *title, char_u *dflt, char_u *ext, char_u *initdir, char_u *filter);
 char_u *gui_mch_browsedir(char_u *title, char_u *initdir);
diff --git a/src/terminal.c b/src/terminal.c
index f644fb5e97..8a4e459c3f 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -4831,8 +4831,15 @@ parse_csi(
 #ifdef FEAT_GUI
 	if (gui.in_use)
 	{
+#ifdef FEAT_GUI_MACVIM
+	    struct cellsize cs;
+	    gui_mch_calc_cell_size(&cs);
+	    x += wp->w_wincol * cs.cs_xpixel;
+	    y += W_WINROW(wp) * cs.cs_ypixel;
+#else
 	    x += wp->w_wincol * gui.char_width;
 	    y += W_WINROW(wp) * gui.char_height;
+#endif
 	}
 	else
 #endif
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 8ecc3a6710..5c77fb3160 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -4338,6 +4338,32 @@ func Test_getcellpixels_gui()
   endif
 endfunc
 
+" Test for getcellpixels() for MacVim
+func Test_getcellpixels_macvim()
+  CheckGui
+  CheckRunVimInTerminal
+  if has("gui_running") && has('gui_macvim')
+    " MacVim works asynchronously and getcellpixels() does not immediately
+    " work either at launch or after guifont has been changed. It's a
+    " deliberate design decision. Right now the caller has to wait for MacVim
+    " to update the state before getcellpixels() will reflect the correct
+    " value, hence the need for multiple wait's here.
+    call WaitForAssert({-> assert_notequal(0, getcellpixels()[0], 'Uninitialized getcellpixels')})
+    call assert_equal([7, 13], getcellpixels()) " Default font is Menlo:h11
+    set guifont=Menlo:h13
+    call WaitForAssert({-> assert_equal([8, 15], getcellpixels())})
+
+    " Also test hosting a terminal and have that be updated
+    let buf = RunVimInTerminal('', #{})
+    call term_sendkeys(buf, ":redi @\"\<CR>")
+    call term_sendkeys(buf, ":echo getcellpixels()\<CR>")
+    call term_sendkeys(buf, ":redi END\<CR>")
+    call term_sendkeys(buf, "P")
+    call WaitForAssert({-> assert_equal(string(getcellpixels()), term_getline(buf, 3))}, 1000)
+    call StopVimInTerminal(buf)
+  endif
+endfunc
+
 func Str2Blob(s)
   return list2blob(str2list(a:s))
 endfunc