diff --git a/var/spack/repos/builtin/packages/qmcpack/package.py b/var/spack/repos/builtin/packages/qmcpack/package.py
index 6d67a670b69..e21908a56fe 100644
--- a/var/spack/repos/builtin/packages/qmcpack/package.py
+++ b/var/spack/repos/builtin/packages/qmcpack/package.py
@@ -370,6 +370,7 @@ def cmake_args(self):
         else:
             args.append("-DBUILD_PPCONVERT=0")
 
+        args.append(self.define("Python3_EXECUTABLE", self.spec["python"].command.path))
         return args
 
     # QMCPACK needs custom install method for the following reason: