diff --git a/app/models/tag.rb b/app/models/tag.rb
index 207d77d73..d985a41cc 100644
--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@@ -23,8 +23,10 @@ class Tag < ApplicationRecord
   validates :name, tag_name: true, uniqueness: true, on: :create
   validates :name, tag_name: true, on: :name
   validates :category, inclusion: { in: TagCategory.category_ids }
+  validate :validate_category, if: :category_changed?
 
   before_create :create_character_tag_for_cosplay_tag, if: :is_cosplay_tag?
+  after_save :update_tag_alias_categories, if: :saved_change_to_category?
   after_save :update_category_cache, if: :saved_change_to_category?
   after_save :update_category_post_counts, if: :saved_change_to_category?
 
@@ -173,6 +175,21 @@ class Tag < ApplicationRecord
     def update_category_cache
       Cache.put("tc:#{Cache.hash(name)}", category, 3.hours)
     end
+
+    # When a tag's category is changed, also change the categories of any aliases pointing to it.
+    def update_tag_alias_categories
+      consequent_aliases.each do |tag_alias|
+        if tag_alias.antecedent_tag.category != category
+          tag_alias.antecedent_tag.update!(category: category, updater: updater)
+        end
+      end
+    end
+
+    def validate_category
+      if is_aliased? && category != aliased_tag.category
+        errors.add(:base, "Can't change the category of an aliased tag")
+      end
+    end
   end
 
   concerning :NameMethods do
diff --git a/script/fixes/131_fix_aliased_tag_categories.rb b/script/fixes/131_fix_aliased_tag_categories.rb
new file mode 100755
index 000000000..5485757a8
--- /dev/null
+++ b/script/fixes/131_fix_aliased_tag_categories.rb
@@ -0,0 +1,15 @@
+#!/usr/bin/env ruby
+
+require_relative "base"
+
+with_confirmation do
+  fix = ENV.fetch("FIX", "false").truthy?
+
+  aliases = TagAlias.active.joins(:antecedent_tag, :consequent_tag).where("tags.category != consequent_tags_tag_aliases.category")
+  aliases.find_each do |tag_alias|
+    tag_alias.antecedent_tag.assign_attributes(category: tag_alias.consequent_tag.category, updater: User.system)
+
+    puts ({ id: tag_alias.id, from: tag_alias.antecedent_tag.name, to: tag_alias.consequent_tag.name, changes: tag_alias.antecedent_tag.changes }).to_json
+    tag_alias.antecedent_tag.save!(touch: false) if fix
+  end
+end
diff --git a/test/unit/post_test.rb b/test/unit/post_test.rb
index 4a64a098c..cb681a514 100644
--- a/test/unit/post_test.rb
+++ b/test/unit/post_test.rb
@@ -587,13 +587,13 @@ class PostTest < ActiveSupport::TestCase
             assert_equal(Tag.categories.character, tag.last_version.category)
           end
 
-          should "change the category for an aliased tag" do
+          should "not change the category for an aliased tag" do
             create(:tag_alias, antecedent_name: "hoge", consequent_name: "moge")
             post = create(:post, tag_string: "char:hoge")
 
             assert_equal(["moge"], post.tag_array)
             assert_equal(Tag.categories.general, Tag.find_by_name("moge").category)
-            assert_equal(Tag.categories.character, Tag.find_by_name("hoge").category)
+            assert_equal(Tag.categories.general, Tag.find_by_name("hoge").category)
           end
 
           should "not raise an exception for an invalid tag name" do
diff --git a/test/unit/tag_test.rb b/test/unit/tag_test.rb
index 27b421c2c..1b8b5034f 100644
--- a/test/unit/tag_test.rb
+++ b/test/unit/tag_test.rb
@@ -175,6 +175,17 @@ class TagTest < ActiveSupport::TestCase
       assert_equal(0, tag.reload.category)
     end
 
+    should "not change category if the tag is aliased" do
+      t1 = create(:tag, name: "ff7", category: Tag.categories.copyright)
+      t2 = create(:tag, name: "final_fantasy_vii", category: Tag.categories.copyright)
+      ta = create(:tag_alias, antecedent_name: "ff7", consequent_name: "final_fantasy_vii")
+
+      t1.reload.category = Tag.categories.character
+
+      assert_equal(false, t1.valid?)
+      assert_equal(["Can't change the category of an aliased tag"], t1.errors[:base])
+    end
+
     should "update post tag counts when the category is changed" do
       post = FactoryBot.create(:post, tag_string: "test")
       assert_equal(1, post.tag_count_general)
@@ -186,6 +197,15 @@ class TagTest < ActiveSupport::TestCase
       assert_equal(1, post.tag_count_character)
     end
 
+    should "update aliased tags when the tag's category is changed" do
+      t1 = create(:tag, name: "ff7", category: Tag.categories.general)
+      t2 = create(:tag, name: "final_fantasy_vii", category: Tag.categories.general)
+      ta = create(:tag_alias, antecedent_name: "ff7", consequent_name: "final_fantasy_vii")
+      t2.update!(category: Tag.categories.copyright, updater: User.system)
+
+      assert_equal("Copyright", t1.reload.category_name)
+    end
+
     should "be created when one doesn't exist" do
       assert_difference("Tag.count", 1) do
         tag = Tag.find_or_create_by_name("hoge")