diff --git a/dev-python/mss/mss-6.0.0.ebuild b/dev-python/mss/mss-6.0.0.ebuild
index b010f45a9639f..28a7a6fe0accb 100644
--- a/dev-python/mss/mss-6.0.0.ebuild
+++ b/dev-python/mss/mss-6.0.0.ebuild
@@ -21,6 +21,7 @@ S="${WORKDIR}/python-${PN}-${PV}"
 BDEPEND="test? (
 	dev-python/flaky[${PYTHON_USEDEP}]
 	dev-python/wheel[${PYTHON_USEDEP}]
+	sys-process/lsof
 )"
 
 distutils_enable_tests pytest