diff --git a/src/testdir/test_timers.vim b/src/testdir/test_timers.vim
index 55f5245..df42b2c 100644
--- a/src/testdir/test_timers.vim
+++ b/src/testdir/test_timers.vim
@@ -124,7 +124,7 @@
   if has('reltime')
     if has('mac')
       " The travis Mac machines appear to be very busy.
-      call assert_inrange(0, 40, slept)
+      call assert_inrange(0, 50, slept)
     else
       call assert_inrange(0, 30, slept)
     endif