diff --git a/kitty/boss.py b/kitty/boss.py
index c522a38ed..9dc237578 100644
--- a/kitty/boss.py
+++ b/kitty/boss.py
@@ -150,7 +150,7 @@ class Boss(Thread):
     def render(self):
         if self.pending_title_change is not None:
             t, self.pending_title_change = sanitize_title(self.pending_title_change or appname), None
-            glfw.glfwSetWindowTitle(self.window, t)
+            glfw.glfwSetWindowTitle(self.window, t.encode('utf-8'))
         if self.pending_icon_change is not None:
             self.pending_icon_change = None  # TODO: Implement this
         self.char_grid.render()
diff --git a/kitty/utils.py b/kitty/utils.py
index f00ee2916..03d8027d0 100644
--- a/kitty/utils.py
+++ b/kitty/utils.py
@@ -35,7 +35,7 @@ def timeit(name, do_timing=False):
 
 
 def sanitize_title(x):
-    return re.sub(br'\s+', b' ', re.sub(br'[\0-\x19]', b'', x))
+    return re.sub(r'\s+', ' ', re.sub(r'[\0-\x19]', '', x))
 
 
 def get_logical_dpi():
diff --git a/kitty_tests/datatypes.py b/kitty_tests/datatypes.py
index 1541b589d..2102a59c0 100644
--- a/kitty_tests/datatypes.py
+++ b/kitty_tests/datatypes.py
@@ -266,7 +266,7 @@ class TestDataTypes(BaseTest):
 
     def test_utils(self):
         self.ae(tuple(map(wcwidth, 'a1\0コ')), (1, 1, 0, 2))
-        self.assertEqual(sanitize_title(b'a\0\01 \t\n\f\rb'), b'a b')
+        self.assertEqual(sanitize_title('a\0\01 \t\n\f\rb'), 'a b')
 
     def test_color_profile(self):
         c = ColorProfile()