diff --git a/flake.nix b/flake.nix
index 806ed45de..f4fae2a00 100644
--- a/flake.nix
+++ b/flake.nix
@@ -667,6 +667,9 @@
               PATH=$prefix/bin:$PATH
               unset PYTHONPATH
               export MANPATH=$out/share/man:$MANPATH
+
+              # Make bash completion work.
+              XDG_DATA_DIRS+=:$out/share
             '';
         });