diff --git a/dev-python/stdio-mgr/stdio-mgr-1.0.1.ebuild b/dev-python/stdio-mgr/stdio-mgr-1.0.1.ebuild
index 1e25644bdaf02..2fb53aef99697 100644
--- a/dev-python/stdio-mgr/stdio-mgr-1.0.1.ebuild
+++ b/dev-python/stdio-mgr/stdio-mgr-1.0.1.ebuild
@@ -15,7 +15,7 @@ HOMEPAGE="
 SRC_URI="https://github.com/bskinn/${PN}/archive/v${PV}.tar.gz -> ${P}.tar.gz"
 
 LICENSE="MIT"
-KEYWORDS="amd64 arm arm64 ~hppa ~ia64 ppc ppc64 ~riscv sparc x86"
+KEYWORDS="amd64 arm arm64 ~hppa ~ia64 ppc ppc64 ~riscv ~s390 sparc x86"
 SLOT="0"
 
 RDEPEND=">=dev-python/attrs-17.1[${PYTHON_USEDEP}]"