diff --git a/requirements.txt b/requirements.txt
index 634ed5c9f27e670734d9d0c25a6b5ce7eeb0797a..a670e1706f81b56bb9e8da65139db7bbc40e35c8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
+numpy
 islpy>=2013.1
 cgen
 git+git://github.com/inducer/pyopencl