diff --git a/var/spack/repos/builtin/packages/chrony/package.py b/var/spack/repos/builtin/packages/chrony/package.py
index a93a3ea69a4..ce87f569e3b 100644
--- a/var/spack/repos/builtin/packages/chrony/package.py
+++ b/var/spack/repos/builtin/packages/chrony/package.py
@@ -21,6 +21,7 @@ class Chrony(AutotoolsPackage):
     version('3.3',   sha256='0dd7323b5ed9e3208236c1b39fcabf2ad03469fa07ac516ba9c682206133f66d')
 
     depends_on('ruby-asciidoctor')
+    depends_on('bison', type='build')
 
     def setup_run_environment(self, env):
         env.prepend_path('PATH', self.prefix.sbin)