diff --git a/src/humanize/time.py b/src/humanize/time.py
index 6653bbd..f6b7fd6 100644
--- a/src/humanize/time.py
+++ b/src/humanize/time.py
@@ -96,7 +96,7 @@ def naturaldelta(
         months (bool): If `True`, then a number of months (based on 30.5 days) will be
             used for fuzziness between years.
         minimum_unit (str): The lowest unit that can be used.
-        when (datetime.timedelta): Point in time relative to which _value_ is
+        when (datetime.datetime): Point in time relative to which _value_ is
             interpreted.  Defaults to the current time in the local timezone.
 
     Returns: