diff --git a/sci-electronics/klayout/klayout-0.30.4.ebuild b/sci-electronics/klayout/klayout-0.30.4.ebuild
index 9eb2afc1ea28..a730a149ce91 100644
--- a/sci-electronics/klayout/klayout-0.30.4.ebuild
+++ b/sci-electronics/klayout/klayout-0.30.4.ebuild
@@ -36,7 +36,9 @@ RDEPEND="
 	${PYTHON_DEPS}
 	$(ruby_implementations_depend)
 "
-DEPEND="${RDEPEND}"
+DEPEND="${RDEPEND}
+	sys-apps/which
+"
 
 pkg_setup() {
 	python-single-r1_pkg_setup
diff --git a/sci-electronics/klayout/klayout-9999.ebuild b/sci-electronics/klayout/klayout-9999.ebuild
index 9379003b9efc..6e89b206eacb 100644
--- a/sci-electronics/klayout/klayout-9999.ebuild
+++ b/sci-electronics/klayout/klayout-9999.ebuild
@@ -36,7 +36,9 @@ RDEPEND="
 	${PYTHON_DEPS}
 	$(ruby_implementations_depend)
 "
-DEPEND="${RDEPEND}"
+DEPEND="${RDEPEND}
+	sys-apps/which
+"
 
 pkg_setup() {
 	python-single-r1_pkg_setup