diff --git a/pkgs/servers/radicale/3.x.nix b/pkgs/servers/radicale/3.x.nix
index 7171b4550fd..a8f5a29db8d 100644
--- a/pkgs/servers/radicale/3.x.nix
+++ b/pkgs/servers/radicale/3.x.nix
@@ -20,6 +20,7 @@ python3.pkgs.buildPythonApplication rec {
     passlib
     vobject
     python-dateutil
+    pytz # https://github.com/Kozea/Radicale/issues/816
   ] ++ passlib.extras-require.bcrypt;
 
   checkInputs = with python3.pkgs; [