diff --git a/backend/app/controllers/nico_tags_controller.rb b/backend/app/controllers/nico_tags_controller.rb
index da3d831..b6acaf2 100644
--- a/backend/app/controllers/nico_tags_controller.rb
+++ b/backend/app/controllers/nico_tags_controller.rb
@@ -6,7 +6,9 @@ class NicoTagsController < ApplicationController
     cursor = params[:cursor].presence
 
     q = Tag.nico_tags
-           .includes(:tag_name, linked_tags: :tag_name)
+           .joins(:tag_name)
+           .left_joins(tag_name: :wiki_page)
+           .includes(:tag_name, tag_name: :wiki_page, linked_tags: :tag_name)
            .order(updated_at: :desc)
     q = q.where('tags.updated_at < ?', Time.iso8601(cursor)) if cursor
 
diff --git a/backend/app/controllers/tags_controller.rb b/backend/app/controllers/tags_controller.rb
index 1c5dcb2..a504f10 100644
--- a/backend/app/controllers/tags_controller.rb
+++ b/backend/app/controllers/tags_controller.rb
@@ -4,10 +4,15 @@ class TagsController < ApplicationController
 
     tags =
         if post_id.present?
-          Tag.joins(:posts).where(posts: { id: post_id })
+          Tag.joins(:posts, :tag_name)
         else
-          Tag.all
+          Tag.joins(:tag_name)
         end
+        .left_joins(tag_name: :wiki_page)
+        .includes(:tag_name, tag_name: :wiki_page)
+    if post_id.present?
+      tags = tags.where(posts: { id: post_id })
+    end
 
     render json: tags.as_json(only: [:id, :category, :post_count], methods: [:name, :has_wiki])
   end
@@ -33,7 +38,9 @@ class TagsController < ApplicationController
       matched_alias_by_tag_name_id[canonical_id] ||= alias_name
     end
 
-    base = Tag.joins(:tag_name).includes(:tag_name)
+    base = Tag.joins(:tag_name)
+              .left_joins(tag_name: :wiki_page)
+              .includes(:tag_name, tag_name: :wiki_page)
     base = base.where('tags.post_count > 0') if present_only
 
     canonical_hit =
@@ -58,7 +65,10 @@ class TagsController < ApplicationController
   end
 
   def show
-    tag = Tag.find_by(id: params[:id])
+    tag = Tag.joins(:tag_name)
+             .left_joins(tag_name: :wiki_page)
+             .includes(:tag_name, tag_name: :wiki_page)
+             .find_by(id: params[:id])
     if tag
       render json: tag.as_json(only: [:id, :category, :post_count], methods: [:name, :has_wiki])
     else
@@ -70,7 +80,10 @@ class TagsController < ApplicationController
     name = params[:name].to_s.strip
     return head :bad_request if name.blank?
 
-    tag = Tag.joins(:tag_name).includes(:tag_name).find_by(tag_names: { name: })
+    tag = Tag.joins(:tag_name)
+             .left_joins(tag_name: :wiki_page)
+             .includes(:tag_name, tag_name: :wiki_page)
+             .find_by(tag_names: { name: })
     if tag
       render json: tag.as_json(only: [:id, :category, :post_count], methods: [:name, :has_wiki])
     else
diff --git a/backend/app/controllers/wiki_pages_controller.rb b/backend/app/controllers/wiki_pages_controller.rb
index 20b2912..e9960ed 100644
--- a/backend/app/controllers/wiki_pages_controller.rb
+++ b/backend/app/controllers/wiki_pages_controller.rb
@@ -3,7 +3,11 @@ class WikiPagesController < ApplicationController
 
   def index
     title = params[:title].to_s.strip
-    return render json: WikiPage.all.as_json(methods: [:title]) if title.blank?
+    if title.blank?
+      return render json: WikiPage.joins(:tag_name)
+                                  .includes(:tag_name)
+                                  .as_json(methods: [:title])
+    end
 
     q = WikiPage.joins(:tag_name).includes(:tag_name)
         .where('tag_names.name LIKE ?', "%#{ WikiPage.sanitize_sql_like(title) }%")