diff --git a/var/spack/repos/builtin/packages/numdiff/package.py b/var/spack/repos/builtin/packages/numdiff/package.py
index a51f6206cf1305b69dc0a9238f9715478301b32e..e72c60fadbe25d0067f2f63a269ce38b51e98b29 100644
--- a/var/spack/repos/builtin/packages/numdiff/package.py
+++ b/var/spack/repos/builtin/packages/numdiff/package.py
@@ -23,6 +23,7 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 from spack import *
+import sys
 
 class Numdiff(Package):
     """Numdiff is a little program that can be used to compare putatively
@@ -34,6 +35,8 @@ class Numdiff(Package):
 
     version('5.8.1',    'a295eb391f6cb1578209fc6b4f9d994e')
 
+    depends_on('gettext', sys.platform=='darwin')
+
     def install(self, spec, prefix):
         options = ['--prefix=%s' % prefix]
         configure(*options)