diff --git a/var/spack/repos/builtin/packages/proj/package.py b/var/spack/repos/builtin/packages/proj/package.py
index 6c62df373fe..eb3c16d6baa 100644
--- a/var/spack/repos/builtin/packages/proj/package.py
+++ b/var/spack/repos/builtin/packages/proj/package.py
@@ -124,7 +124,7 @@ def cmake_args(self):
             self.define_from_variant("ENABLE_TIFF", "tiff"),
             self.define_from_variant("ENABLE_CURL", "curl"),
         ]
-        if self.spec.satisfies("@6:"):
+        if self.spec.satisfies("@6:") and self.pkg.run_tests:
             args.append(self.define("USE_EXTERNAL_GTEST", True))
         return args