diff --git a/adafruit_display_text/label.py b/adafruit_display_text/label.py
index a8b64c9..a1f467f 100755
--- a/adafruit_display_text/label.py
+++ b/adafruit_display_text/label.py
@@ -141,8 +141,9 @@ def _create_background_box(self, lines, y_offset):
             ascender_max = descender_max = 0
             for char in glyphs:
                 this_glyph = self._font.get_glyph(ord(char))
-                ascender_max = max(ascender_max, this_glyph.height + this_glyph.dy)
-                descender_max = max(descender_max, -this_glyph.dy)
+                if this_glyph:
+                    ascender_max = max(ascender_max, this_glyph.height + this_glyph.dy)
+                    descender_max = max(descender_max, -this_glyph.dy)
 
             box_width = self._boundingbox[2] + self._padding_left + self._padding_right
             x_box_offset = -self._padding_left