diff --git a/var/spack/repos/builtin/packages/mariadb/package.py b/var/spack/repos/builtin/packages/mariadb/package.py
index 54489486a5f..f389e7d55f6 100644
--- a/var/spack/repos/builtin/packages/mariadb/package.py
+++ b/var/spack/repos/builtin/packages/mariadb/package.py
@@ -35,3 +35,5 @@ class Mariadb(CMakePackage):
     depends_on('libevent', when='+nonblocking')
     depends_on('ncurses')
     depends_on('zlib')
+
+    conflicts('%gcc@9.1.0:', when='@:5.5')