diff --git a/app/models/post_mover.rb b/app/models/post_mover.rb
index 5ac0a416a5..6c494810dc 100644
--- a/app/models/post_mover.rb
+++ b/app/models/post_mover.rb
@@ -76,6 +76,7 @@ class PostMover
     update_user_actions
     update_last_post_stats
     update_upload_security_status
+    update_bookmarks
 
     if moving_all_posts
       @original_topic.update_status('closed', true, @user)
@@ -491,6 +492,10 @@ class PostMover
     end
   end
 
+  def update_bookmarks
+    Bookmark.where(post_id: post_ids).update_all(topic_id: @destination_topic.id)
+  end
+
   def watch_new_topic
     if @destination_topic.archetype == Archetype.private_message
       if @original_topic.archetype == Archetype.private_message
diff --git a/db/post_migrate/20210328233843_fix_bookmarks_with_incorrect_topic_id.rb b/db/post_migrate/20210328233843_fix_bookmarks_with_incorrect_topic_id.rb
new file mode 100644
index 0000000000..0c735dce62
--- /dev/null
+++ b/db/post_migrate/20210328233843_fix_bookmarks_with_incorrect_topic_id.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class FixBookmarksWithIncorrectTopicId < ActiveRecord::Migration[6.0]
+  def up
+    result = DB.exec(<<~SQL)
+      UPDATE bookmarks bm
+      SET topic_id = subquery.correct_topic_id, updated_at = NOW()
+      FROM (
+        SELECT bookmarks.id AS bookmark_id, bookmarks.post_id, bookmarks.topic_id,
+               posts.topic_id AS correct_topic_id
+        FROM bookmarks
+        INNER JOIN posts ON posts.id = bookmarks.post_id
+        WHERE posts.topic_id != bookmarks.topic_id
+      ) AS subquery
+      WHERE bm.id = subquery.bookmark_id;
+    SQL
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end
diff --git a/spec/models/post_mover_spec.rb b/spec/models/post_mover_spec.rb
index 018c850a3e..0cf705f7b2 100644
--- a/spec/models/post_mover_spec.rb
+++ b/spec/models/post_mover_spec.rb
@@ -385,6 +385,20 @@ describe PostMover do
               .to contain_exactly([1, 500], [2, 750])
           end
 
+          it "updates bookmark topic_ids to the new topic id and does not affect bookmarks for posts not moving" do
+            some_user = Fabricate(:user)
+            new_post = Fabricate(:post, topic: p1.topic)
+            bookmark1 = Fabricate(:bookmark, topic: p1.topic, post: p1, user: some_user)
+            bookmark2 = Fabricate(:bookmark, topic: p4.topic, post: p4)
+            bookmark3 = Fabricate(:bookmark, topic: p4.topic, post: p4)
+            bookmark4 = Fabricate(:bookmark, topic: new_post.topic, post: new_post)
+            new_topic = topic.move_posts(user, [p1.id, p4.id], title: "new testing topic name")
+            expect(bookmark1.reload.topic_id).to eq(new_topic.id)
+            expect(bookmark2.reload.topic_id).to eq(new_topic.id)
+            expect(bookmark3.reload.topic_id).to eq(new_topic.id)
+            expect(bookmark4.reload.topic_id).to eq(new_post.topic_id)
+          end
+
           context "read state and other stats per user" do
             def create_topic_user(user, opts = {})
               notification_level = opts.delete(:notification_level) || :regular
@@ -600,6 +614,20 @@ describe PostMover do
             expect(Notification.exists?(admin_notification.id)).to eq(true)
           end
 
+          it "updates bookmark topic_ids to the new topic id and does not affect bookmarks for posts not moving" do
+            some_user = Fabricate(:user)
+            new_post = Fabricate(:post, topic: p3.topic)
+            bookmark1 = Fabricate(:bookmark, topic: p3.topic, post: p3, user: some_user)
+            bookmark2 = Fabricate(:bookmark, topic: p3.topic, post: p3)
+            bookmark3 = Fabricate(:bookmark, topic: p3.topic, post: p3)
+            bookmark4 = Fabricate(:bookmark, topic: new_post.topic, post: new_post)
+            topic.move_posts(user, [p3.id], destination_topic_id: destination_topic.id)
+            expect(bookmark1.reload.topic_id).to eq(destination_topic.id)
+            expect(bookmark2.reload.topic_id).to eq(destination_topic.id)
+            expect(bookmark3.reload.topic_id).to eq(destination_topic.id)
+            expect(bookmark4.reload.topic_id).to eq(new_post.topic_id)
+          end
+
           context "post timings" do
             fab!(:some_user) { Fabricate(:user) }