diff --git a/Lib/idlelib/idle_test/test_tooltip.py b/Lib/idlelib/idle_test/test_tooltip.py
index 44ea1110e155dc..2debd3229afa90 100644
--- a/Lib/idlelib/idle_test/test_tooltip.py
+++ b/Lib/idlelib/idle_test/test_tooltip.py
@@ -102,7 +102,8 @@ def test_showtip_on_mouse_enter_no_delay(self):
         self.assertGreater(len(tooltip.showtip.call_args_list), 0)
 
     def test_showtip_on_mouse_enter_hover_delay(self):
-        tooltip = Hovertip(self.button, 'ToolTip text', hover_delay=50)
+        # Fragile test -- see issue 35771.
+        tooltip = Hovertip(self.button, 'ToolTip text', hover_delay=100)
         self.addCleanup(tooltip.hidetip)
         tooltip.showtip = add_call_counting(tooltip.showtip)
         root_update()
@@ -110,7 +111,7 @@ def test_showtip_on_mouse_enter_hover_delay(self):
         self.button.event_generate('<Enter>', x=0, y=0)
         root_update()
         self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
-        time.sleep(0.1)
+        time.sleep(0.15)
         root_update()
         self.assertTrue(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
         self.assertGreater(len(tooltip.showtip.call_args_list), 0)
@@ -128,7 +129,7 @@ def test_hidetip_on_mouse_leave(self):
         self.assertGreater(len(tooltip.showtip.call_args_list), 0)
 
     def test_dont_show_on_mouse_leave_before_delay(self):
-        tooltip = Hovertip(self.button, 'ToolTip text', hover_delay=50)
+        tooltip = Hovertip(self.button, 'ToolTip text', hover_delay=100)
         self.addCleanup(tooltip.hidetip)
         tooltip.showtip = add_call_counting(tooltip.showtip)
         root_update()
@@ -136,7 +137,7 @@ def test_dont_show_on_mouse_leave_before_delay(self):
         root_update()
         self.button.event_generate('<Leave>', x=0, y=0)
         root_update()
-        time.sleep(0.1)
+        time.sleep(0.15)
         root_update()
         self.assertFalse(tooltip.tipwindow and tooltip.tipwindow.winfo_viewable())
         self.assertEqual(tooltip.showtip.call_args_list, [])
diff --git a/Misc/NEWS.d/next/IDLE/2019-08-03-05-27-39.bpo-35771.LfQWI-.rst b/Misc/NEWS.d/next/IDLE/2019-08-03-05-27-39.bpo-35771.LfQWI-.rst
new file mode 100644
index 00000000000000..cb3c239e207e25
--- /dev/null
+++ b/Misc/NEWS.d/next/IDLE/2019-08-03-05-27-39.bpo-35771.LfQWI-.rst
@@ -0,0 +1 @@
+Increase the ``hover_delay`` in IDLE's test_tooltip.