diff --git a/pymbolic/mapper/evaluator.py b/pymbolic/mapper/evaluator.py
index aed88761a7ae88b0156bdee3f27597c72cc42972..aea4ce7982e8f6cca5372bd044d4f8c761091a43 100644
--- a/pymbolic/mapper/evaluator.py
+++ b/pymbolic/mapper/evaluator.py
@@ -25,6 +25,7 @@ THE SOFTWARE.
 
 from pymbolic.mapper import RecursiveMapper, CSECachingMapperMixin
 import operator as op
+from six.moves import reduce
 
 
 class UnknownVariableError(Exception):