diff --git a/pymbolic/mapper/differentiator.py b/pymbolic/mapper/differentiator.py
index 8f613f54ffae3ad04258e1a4debedaf9c7981b4e..0d79b92b35c34067ae6045a1beb53e1cfa75aaba 100644
--- a/pymbolic/mapper/differentiator.py
+++ b/pymbolic/mapper/differentiator.py
@@ -123,6 +123,14 @@ class DifferentiationMapper(pymbolic.mapper.RecursiveMapper):
                 Polynomial(expr.base, tuple(deriv_coeff), expr.unit) + \
                 Polynomial(expr.base, tuple(deriv_base), expr.unit)
   
+    def map_numpy_array(self, expr):
+        import numpy
+        result = numpy.empty(expr.shape, dtype=object)
+        from pytools import indices_in_shape
+        for i in indices_in_shape(expr.shape):
+            result[i] = self.rec(expr[i])
+        return result
+