diff --git a/khal/icalendar.py b/khal/icalendar.py
index 39e6eda8f..3d1fcd71f 100644
--- a/khal/icalendar.py
+++ b/khal/icalendar.py
@@ -37,6 +37,10 @@
 
 logger = logging.getLogger('khal')
 
+# Force use of pytz because we rely on functionalities not available in
+# zoneinfo.
+icalendar.use_pytz()
+
 
 def split_ics(ics: str, random_uid: bool=False, default_timezone=None) -> List:
     """split an ics string into several according to VEVENT's UIDs