diff --git a/boards/admin.py b/boards/admin.py
--- a/boards/admin.py
+++ b/boards/admin.py
@@ -34,6 +34,11 @@ class TagAdmin(admin.ModelAdmin):
     def display_children(self, obj: Tag):
         return ', '.join([str(child) for child in obj.get_children().all()])
 
+    def save_model(self, request, obj, form, change):
+        super().save_model(request, obj, form, change)
+        for thread in obj.get_threads().all():
+            thread.refresh_tags()
+
     list_display = ('name', 'thread_count', 'display_children')
     search_fields = ('name',)
 
@@ -59,11 +64,7 @@ class ThreadAdmin(admin.ModelAdmin):
     # Save parent tags when editing tags
     def save_related(self, request, form, formsets, change):
         super().save_related(request, form, formsets, change)
-        obj = form.instance
-        for tag in obj.get_tags().all():
-            parents = tag.get_all_parents()
-            if len(parents) > 0:
-                obj.tags.add(*parents)
+        form.instance.refresh_tags()
 
     list_display = ('id', 'op', 'title', 'reply_count', 'status', 'ip',
             'display_tags')
diff --git a/boards/models/thread.py b/boards/models/thread.py
--- a/boards/models/thread.py
+++ b/boards/models/thread.py
@@ -3,7 +3,7 @@ from adjacent import Client
 
 from django.db.models import Count, Sum, QuerySet, Q
 from django.utils import timezone
-from django.db import models
+from django.db import models, transaction
 
 from boards.models import STATUS_BUMPLIMIT, STATUS_ACTIVE, STATUS_ARCHIVE
 
@@ -270,3 +270,12 @@ class Thread(models.Model):
 
     def is_monochrome(self):
         return self.monochrome
+
+    # If tags have parent, add them to the tag list
+    @transaction.atomic
+    def refresh_tags(self):
+        for tag in self.get_tags().all():
+            parents = tag.get_all_parents()
+            if len(parents) > 0:
+                self.tags.add(*parents)
+