diff --git a/wagtail/wagtailcore/models.py b/wagtail/wagtailcore/models.py
index 8c6c55335d..d322ab69b5 100644
--- a/wagtail/wagtailcore/models.py
+++ b/wagtail/wagtailcore/models.py
@@ -558,6 +558,15 @@ class Page(MP_Node, ClusterableModel, Indexed):
         user_perms = UserPagePermissionsProxy(user)
         return user_perms.for_page(self)
 
+    def get_ancestors(self, inclusive=False):
+        return Page.objects.ancestor_of(self, inclusive)
+
+    def get_descendants(self, inclusive=False):
+        return Page.objects.descendant_of(self, inclusive)
+
+    def get_siblings(self, inclusive=True):
+        return Page.objects.sibling_of(self, inclusive)
+
 
 def get_navigation_menu_items():
     # Get all pages that appear in the navigation menu: ones which have children,
diff --git a/wagtail/wagtailcore/query.py b/wagtail/wagtailcore/query.py
index d182ec5887..048ccda063 100644
--- a/wagtail/wagtailcore/query.py
+++ b/wagtail/wagtailcore/query.py
@@ -84,7 +84,7 @@ class PageQuerySet(MP_NodeQuerySet):
     def not_parent_of(self, other):
         return self.exclude(self.parent_of_q(other))
 
-    def sibling_of_q(self, other, inclusive=False):
+    def sibling_of_q(self, other, inclusive=True):
         q = Q(path__startswith=self.model._get_parent_path_from_path(other.path)) & Q(depth=other.depth)
 
         if not inclusive:
@@ -92,10 +92,10 @@ class PageQuerySet(MP_NodeQuerySet):
 
         return q
 
-    def sibling_of(self, other, inclusive=False):
+    def sibling_of(self, other, inclusive=True):
         return self.filter(self.sibling_of_q(other, inclusive))
 
-    def not_sibling_of(self, other, inclusive=False):
+    def not_sibling_of(self, other, inclusive=True):
         return self.exclude(self.sibling_of_q(other, inclusive))
 
     def type_q(self, model):