diff --git a/source/blender/editors/grease_pencil/intern/grease_pencil_frames.cc b/source/blender/editors/grease_pencil/intern/grease_pencil_frames.cc
index 04017d7ab3f..05de8b9a696 100644
--- a/source/blender/editors/grease_pencil/intern/grease_pencil_frames.cc
+++ b/source/blender/editors/grease_pencil/intern/grease_pencil_frames.cc
@@ -27,6 +27,16 @@
 
 namespace blender::ed::greasepencil {
 
+void set_selected_frames_type(bke::greasepencil::Layer &layer,
+                              const eBezTriple_KeyframeType key_type)
+{
+  for (GreasePencilFrame &frame : layer.frames_for_write().values()) {
+    if (frame.is_selected()) {
+      frame.type = key_type;
+    }
+  }
+}
+
 bool remove_all_selected_frames(GreasePencil &grease_pencil, bke::greasepencil::Layer &layer)
 {
   Vector<int> frames_to_remove;
diff --git a/source/blender/editors/include/ED_grease_pencil.hh b/source/blender/editors/include/ED_grease_pencil.hh
index 656c03e3bc7..e368cc25e44 100644
--- a/source/blender/editors/include/ED_grease_pencil.hh
+++ b/source/blender/editors/include/ED_grease_pencil.hh
@@ -47,6 +47,9 @@ eAttrDomain ED_grease_pencil_selection_domain_get(bContext *C);
 
 namespace blender::ed::greasepencil {
 
+void set_selected_frames_type(bke::greasepencil::Layer &layer,
+                              const eBezTriple_KeyframeType key_type);
+
 bool remove_all_selected_frames(GreasePencil &grease_pencil, bke::greasepencil::Layer &layer);
 
 void select_layer_channel(GreasePencil &grease_pencil, bke::greasepencil::Layer *layer);
diff --git a/source/blender/editors/space_action/action_edit.cc b/source/blender/editors/space_action/action_edit.cc
index f24e2ca8f41..1c3ad86658b 100644
--- a/source/blender/editors/space_action/action_edit.cc
+++ b/source/blender/editors/space_action/action_edit.cc
@@ -1662,7 +1662,10 @@ static void setkeytype_action_keys(bAnimContext *ac, short mode)
         break;
 
       case ANIMTYPE_GREASE_PENCIL_LAYER:
-        /* GPv3: To be implemented. */
+        blender::ed::greasepencil::set_selected_frames_type(
+            static_cast<GreasePencilLayer *>(ale->data)->wrap(),
+            static_cast<eBezTriple_KeyframeType>(mode));
+        ale->update |= ANIM_UPDATE_DEPS;
         break;
 
       case ANIMTYPE_FCURVE: