diff --git a/var/spack/repos/builtin/packages/geant4-vmc/package.py b/var/spack/repos/builtin/packages/geant4-vmc/package.py
index 941e87570d..4b75b17f7b 100644
--- a/var/spack/repos/builtin/packages/geant4-vmc/package.py
+++ b/var/spack/repos/builtin/packages/geant4-vmc/package.py
@@ -36,3 +36,7 @@ class Geant4Vmc(CMakePackage):
     depends_on("cmake@3.3:", type="build")
     depends_on("geant4")
     depends_on("vmc")
+
+    def setup_build_environment(self, env):
+        if self.spec.satisfies("platform=darwin"):
+            env.unset("MACOSX_DEPLOYMENT_TARGET")