diff --git a/gtk/gtkstylecontext.h b/gtk/gtkstylecontext.h
index 805f787fd6..daf997fa08 100644
--- a/gtk/gtkstylecontext.h
+++ b/gtk/gtkstylecontext.h
@@ -241,6 +241,13 @@ struct _GtkStyleContextClass
  */
 #define GTK_STYLE_CLASS_PRIMARY_TOOLBAR "primary-toolbar"
 
+/**
+ * GTK_STYLE_CLASS_INLINE_TOOLBAR:
+ *
+ * A CSS class to match inline toolbars.
+ */
+#define GTK_STYLE_CLASS_INLINE_TOOLBAR "inline-toolbar"
+
 /**
  * GTK_STYLE_CLASS_RADIO:
  *