diff --git a/dev-python/pyproject-fmt/pyproject-fmt-0.3.5.ebuild b/dev-python/pyproject-fmt/pyproject-fmt-0.3.5.ebuild
index 7d9a843ce7aee..142f153fd0ba0 100644
--- a/dev-python/pyproject-fmt/pyproject-fmt-0.3.5.ebuild
+++ b/dev-python/pyproject-fmt/pyproject-fmt-0.3.5.ebuild
@@ -20,7 +20,7 @@ SRC_URI="
 
 LICENSE="MIT"
 SLOT="0"
-KEYWORDS="~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~ppc ~ppc64 ~riscv ~sparc ~x86"
+KEYWORDS="~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86"
 
 RDEPEND="
 	>=dev-python/packaging-21.3[${PYTHON_USEDEP}]