diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 93efaec..cc19e25 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1087,7 +1087,9 @@
 <	Use 'backupdir' to put the backup in a different directory.
 
 						*'backupskip'* *'bsk'*
-'backupskip' 'bsk'	string	(default: "/tmp/*,$TMPDIR/*,$TMP/*,$TEMP/*")
+'backupskip' 'bsk'	string	(default: "$TMPDIR/*,$TMP/*,$TEMP/*"
+				 Unix: "/tmp/*,$TMPDIR/*,$TMP/*,$TEMP/*"
+				 Mac: "/private/tmp/*,$TMPDIR/*,$TMP/*,$TEMP/*")
 			global
 			{not in Vi}
 			{not available when compiled without the |+wildignore|
diff --git a/src/option.c b/src/option.c
index 48432bb..5ef346c 100644
--- a/src/option.c
+++ b/src/option.c
@@ -3367,7 +3367,11 @@
 	    mustfree = FALSE;
 # ifdef UNIX
 	    if (*names[n] == NUL)
+#  ifdef MACOS_X
+		p = (char_u *)"/private/tmp";
+#  else
 		p = (char_u *)"/tmp";
+#  endif
 	    else
 # endif
 		p = vim_getenv((char_u *)names[n], &mustfree);
diff --git a/src/testdir/test_options.vim b/src/testdir/test_options.vim
index 5d2033a..0f2908f 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -332,3 +332,19 @@
   call assert_equal('', &indentexpr)
   bwipe!
 endfunc
+
+func Test_backupskip()
+  if has("mac")
+    call assert_match('/private/tmp/\*', &bsk)
+  elseif has("unix")
+    call assert_match('/tmp/\*', &bsk)
+  endif
+
+  let bskvalue = substitute(&bsk, '\\', '/', 'g')
+  for var in  ['$TEMPDIR', '$TMP', '$TEMP']
+    if exists(var)
+      let varvalue = substitute(expand(var), '\\', '/', 'g')
+      call assert_match(varvalue . '.\*', bskvalue)
+    endif
+  endfor
+endfunc
diff --git a/src/version.c b/src/version.c
index fdaa1dc..8d7049d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1704,
+/**/
     1703,
 /**/
     1702,