diff --git a/src/st/st-theme.c b/src/st/st-theme.c
index e9716fe63..d1bde3fc0 100644
--- a/src/st/st-theme.c
+++ b/src/st/st-theme.c
@@ -254,7 +254,7 @@ insert_stylesheet (StTheme      *theme,
  * st_theme_load_stylesheet:
  * @theme: a #StTheme
  * @file: a #GFile
- * @error: (optional): a #GError
+ * @error: a #GError
  *
  * Load the stylesheet associated with @file.
  *