diff --git a/Cython/Includes/numpy/math.pxd b/Cython/Includes/numpy/math.pxd
index b5325ea462c091f3be9ed6f57ffa804bb0f1ca12..9c81284634639119888cbc6177485a46d92d4fa3 100644
--- a/Cython/Includes/numpy/math.pxd
+++ b/Cython/Includes/numpy/math.pxd
@@ -17,7 +17,7 @@
 #
 # Author: Lars Buitinck
 
-cdef extern from "numpy/npy_math.h":
+cdef extern from "numpy/npy_math.h" nogil:
     # Floating-point classification
     long double NAN "NPY_NAN"
     long double INFINITY "NPY_INFINITY"