diff --git a/dev-python/traitlets/traitlets-4.1.0.ebuild b/dev-python/traitlets/traitlets-4.1.0.ebuild
index 87b479c4838e4..29f5b79d3e7a7 100644
--- a/dev-python/traitlets/traitlets-4.1.0.ebuild
+++ b/dev-python/traitlets/traitlets-4.1.0.ebuild
@@ -20,6 +20,7 @@ IUSE="doc test"
 RDEPEND="
 	dev-python/decorator[${PYTHON_USEDEP}]
 	dev-python/ipython_genutils[${PYTHON_USEDEP}]
+	dev-python/six[${PYTHON_USEDEP}]
 	"
 DEPEND="
 	doc? (
diff --git a/dev-python/traitlets/traitlets-4.2.1.ebuild b/dev-python/traitlets/traitlets-4.2.1.ebuild
index 369bd3ef7f022..2cdcd6a8c7845 100644
--- a/dev-python/traitlets/traitlets-4.2.1.ebuild
+++ b/dev-python/traitlets/traitlets-4.2.1.ebuild
@@ -20,6 +20,7 @@ IUSE="doc test"
 RDEPEND="
 	dev-python/decorator[${PYTHON_USEDEP}]
 	dev-python/ipython_genutils[${PYTHON_USEDEP}]
+	dev-python/six[${PYTHON_USEDEP}]
 	"
 DEPEND="
 	doc? (