diff --git a/var/spack/repos/builtin/packages/nwchem/package.py b/var/spack/repos/builtin/packages/nwchem/package.py
index c90a90b031..09a8c6ed85 100644
--- a/var/spack/repos/builtin/packages/nwchem/package.py
+++ b/var/spack/repos/builtin/packages/nwchem/package.py
@@ -100,7 +100,7 @@ def install(self, spec, prefix):
 
         if "+fftw3" in spec:
             args.extend(["USE_FFTW3=y"])
-            args.extend(["FFTW3_LIB=%s" % fftw.ld_flags])
+            args.extend(["LIBFFTW3=%s" % fftw.ld_flags])
             args.extend(["FFTW3_INCLUDE={0}".format(spec["fftw-api"].prefix.include)])
 
         with working_dir("src"):