diff --git a/var/spack/repos/builtin/packages/charliecloud/package.py b/var/spack/repos/builtin/packages/charliecloud/package.py
index 2db0ecfe9d3..0e562b6997e 100644
--- a/var/spack/repos/builtin/packages/charliecloud/package.py
+++ b/var/spack/repos/builtin/packages/charliecloud/package.py
@@ -33,6 +33,8 @@ class Charliecloud(AutotoolsPackage):
     depends_on('py-sphinx',           type='build', when='+docs')
     depends_on('py-sphinx-rtd-theme', type='build', when='+docs')
 
+    conflicts('platform=darwin', msg='This package does not build on macOS')
+
     # bash automated testing harness (bats)
     depends_on('bats@0.4.0', type='test')