diff --git a/src/core/lv_group.c b/src/core/lv_group.c
index f7a7cbb14e..f038fd6a76 100644
--- a/src/core/lv_group.c
+++ b/src/core/lv_group.c
@@ -75,6 +75,7 @@ lv_group_t * lv_group_create(void)
 void lv_group_delete(lv_group_t * group)
 {
     /*Defocus the currently focused object*/
+    LV_ASSERT_NULL(group);
     if(group->obj_focus != NULL) {
         lv_obj_send_event(*group->obj_focus, LV_EVENT_DEFOCUSED, get_indev(group));
         lv_obj_invalidate(*group->obj_focus);
@@ -220,6 +221,8 @@ void lv_group_remove_obj(lv_obj_t * obj)
 
 void lv_group_remove_all_objs(lv_group_t * group)
 {
+    LV_ASSERT_NULL(group);
+
     /*Defocus the currently focused object*/
     if(group->obj_focus != NULL) {
         lv_obj_send_event(*group->obj_focus, LV_EVENT_DEFOCUSED, get_indev(group));
@@ -271,6 +274,8 @@ void lv_group_focus_obj(lv_obj_t * obj)
 
 void lv_group_focus_next(lv_group_t * group)
 {
+    LV_ASSERT_NULL(group);
+
     bool focus_changed = focus_next_core(group, _lv_ll_get_head, _lv_ll_get_next);
     if(group->edge_cb) {
         if(!focus_changed)
@@ -280,6 +285,8 @@ void lv_group_focus_next(lv_group_t * group)
 
 void lv_group_focus_prev(lv_group_t * group)
 {
+    LV_ASSERT_NULL(group);
+
     bool focus_changed = focus_next_core(group, _lv_ll_get_tail, _lv_ll_get_prev);
     if(group->edge_cb) {
         if(!focus_changed)
@@ -289,12 +296,16 @@ void lv_group_focus_prev(lv_group_t * group)
 
 void lv_group_focus_freeze(lv_group_t * group, bool en)
 {
+    LV_ASSERT_NULL(group);
+
     if(en == false) group->frozen = 0;
     else group->frozen = 1;
 }
 
 lv_result_t lv_group_send_data(lv_group_t * group, uint32_t c)
 {
+    LV_ASSERT_NULL(group);
+
     lv_obj_t * act = lv_group_get_focused(group);
     if(act == NULL) return LV_RESULT_OK;
 
@@ -305,17 +316,21 @@ lv_result_t lv_group_send_data(lv_group_t * group, uint32_t c)
 
 void lv_group_set_focus_cb(lv_group_t * group, lv_group_focus_cb_t focus_cb)
 {
+    if(group == NULL) return;
+
     group->focus_cb = focus_cb;
 }
 
 void lv_group_set_edge_cb(lv_group_t * group, lv_group_edge_cb_t edge_cb)
 {
+    LV_ASSERT_NULL(group);
+
     group->edge_cb = edge_cb;
 }
 
 void lv_group_set_editing(lv_group_t * group, bool edit)
 {
-    if(group == NULL) return;
+    LV_ASSERT_NULL(group);
     uint8_t en_val = edit ? 1 : 0;
 
     if(en_val == group->editing) return; /*Do not set the same mode again*/
@@ -333,11 +348,13 @@ void lv_group_set_editing(lv_group_t * group, bool edit)
 
 void lv_group_set_refocus_policy(lv_group_t * group, lv_group_refocus_policy_t policy)
 {
+    LV_ASSERT_NULL(group);
     group->refocus_policy = policy & 0x01;
 }
 
 void lv_group_set_wrap(lv_group_t * group, bool en)
 {
+    LV_ASSERT_NULL(group);
     group->wrap = en ? 1 : 0;
 }
 
@@ -375,6 +392,7 @@ bool lv_group_get_wrap(lv_group_t * group)
 
 uint32_t lv_group_get_obj_count(lv_group_t * group)
 {
+    LV_ASSERT_NULL(group);
     return _lv_ll_get_len(&group->obj_ll);
 }