diff --git a/qutebrowser/keyinput/keyutils.py b/qutebrowser/keyinput/keyutils.py
index 61e3e53b4..3518e53dd 100644
--- a/qutebrowser/keyinput/keyutils.py
+++ b/qutebrowser/keyinput/keyutils.py
@@ -40,7 +40,7 @@ _MODIFIER_MAP = {
 
 
 def is_printable(key):
-    return key <= 0xff
+    return key <= 0xff and key != Qt.Key_Space
 
 
 def is_modifier_key(key):
@@ -221,7 +221,7 @@ class KeyInfo:
             modifiers &= ~_MODIFIER_MAP[self.key]
         elif is_printable(self.key):
             # "normal" binding
-            assert len(key_string) == 1 or self.key == Qt.Key_Space, key_string
+            assert len(key_string) == 1, key_string
             if self.modifiers == Qt.ShiftModifier:
                 return key_string.upper()
             elif self.modifiers == Qt.NoModifier:
diff --git a/tests/unit/keyinput/test_keyutils.py b/tests/unit/keyinput/test_keyutils.py
index 7fc6cc12c..2e595c19a 100644
--- a/tests/unit/keyinput/test_keyutils.py
+++ b/tests/unit/keyinput/test_keyutils.py
@@ -122,6 +122,8 @@ class TestKeyToString:
     (Qt.Key_A, Qt.NoModifier, 'a'),
     (Qt.Key_A, Qt.ShiftModifier, 'A'),
 
+    (Qt.Key_Space, Qt.NoModifier, '<Space>'),
+    (Qt.Key_Space, Qt.ShiftModifier, '<Shift+Space>'),
     (Qt.Key_Tab, Qt.ShiftModifier, '<Shift+Tab>'),
     (Qt.Key_A, Qt.ControlModifier, '<Ctrl+a>'),
     (Qt.Key_A, Qt.ControlModifier | Qt.ShiftModifier, '<Ctrl+Shift+a>'),
@@ -180,9 +182,9 @@ def test_normalize_keystr(orig, normalized):
     (Qt.Key_Backspace, False),
     (Qt.Key_Return, False),
     (Qt.Key_Enter, False),
+    (Qt.Key_Space, False),
     (Qt.Key_X | Qt.ControlModifier, False),  # Wrong usage
 
-    (Qt.Key_Space, True),  # FIXME broken with upper/lower!
     (Qt.Key_ydiaeresis, True),
     (Qt.Key_X, True),
 ])