diff --git a/lib/wibox/layout/fixed.lua.in b/lib/wibox/layout/fixed.lua.in
index 33c3ad16..343a4150 100644
--- a/lib/wibox/layout/fixed.lua.in
+++ b/lib/wibox/layout/fixed.lua.in
@@ -147,7 +147,8 @@ function fixed.vertical()
     return get_layout("y")
 end
 
--- Add spacing between each layout widgets
+--- Add spacing between each layout widgets
+-- @param spacing Spacing between widgets.
 function fixed:set_spacing(spacing)
     self._spacing = spacing
     self:emit_signal("widget::updated")
diff --git a/lib/wibox/layout/flex.lua.in b/lib/wibox/layout/flex.lua.in
index 083735e6..51293eb9 100644
--- a/lib/wibox/layout/flex.lua.in
+++ b/lib/wibox/layout/flex.lua.in
@@ -148,7 +148,8 @@ function flex.vertical()
     return get_layout("y")
 end
 
--- Add spacing between each layout widgets
+--- Add spacing between each layout widgets
+-- @param spacing Spacing between widgets.
 function flex:set_spacing(spacing)
     self._spacing = spacing
     self:emit_signal("widget::updated")