diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 048a54fdb0..8d6203b99d 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -142,7 +142,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
   end
 
   def valid_status?
-    !Admin::NgWord.reject?("#{@params[:spoiler_text]}\n#{@params[:text]}")
+    !Admin::NgWord.reject?("#{@params[:spoiler_text]}\n#{@params[:text]}") && !Admin::NgWord.hashtag_reject?(@tags.size)
   end
 
   def reply_to_local_account?
diff --git a/app/models/admin/ng_word.rb b/app/models/admin/ng_word.rb
index 3051c5d1bb..878151f648 100644
--- a/app/models/admin/ng_word.rb
+++ b/app/models/admin/ng_word.rb
@@ -6,10 +6,23 @@ class Admin::NgWord
       ng_words.any? { |word| text.include?(word) }
     end
 
+    def hashtag_reject?(hashtag_count)
+      post_hash_tags_max.positive? && post_hash_tags_max < hashtag_count
+    end
+
+    def hashtag_reject_with_extractor?(text)
+      hashtag_reject?(Extractor.extract_hashtags(text)&.size || 0)
+    end
+
     private
 
     def ng_words
       Setting.ng_words
     end
+
+    def post_hash_tags_max
+      value = Setting.post_hash_tags_max
+      value.is_a?(Integer) && value.positive? ? value : 0
+    end
   end
 end
diff --git a/app/models/form/admin_settings.rb b/app/models/form/admin_settings.rb
index 2b77353783..ff7ef50c12 100644
--- a/app/models/form/admin_settings.rb
+++ b/app/models/form/admin_settings.rb
@@ -37,12 +37,14 @@ class Form::AdminSettings
     ng_words
     enable_block_emoji_reaction_settings
     hide_local_users_for_anonymous
+    post_hash_tags_max
   ).freeze
 
   INTEGER_KEYS = %i(
     media_cache_retention_period
     content_cache_retention_period
     backups_retention_period
+    post_hash_tags_max
   ).freeze
 
   BOOLEAN_KEYS = %i(
diff --git a/app/services/activitypub/process_status_update_service.rb b/app/services/activitypub/process_status_update_service.rb
index edfd2b315b..e058290cf4 100644
--- a/app/services/activitypub/process_status_update_service.rb
+++ b/app/services/activitypub/process_status_update_service.rb
@@ -153,7 +153,7 @@ class ActivityPub::ProcessStatusUpdateService < BaseService
   end
 
   def valid_status?
-    !Admin::NgWord.reject?("#{@status_parser.spoiler_text}\n#{@status_parser.text}")
+    !Admin::NgWord.reject?("#{@status_parser.spoiler_text}\n#{@status_parser.text}") && !Admin::NgWord.hashtag_reject?(@tags.size)
   end
 
   def update_immediate_attributes!
diff --git a/app/services/post_status_service.rb b/app/services/post_status_service.rb
index 806afed340..08d3f1998a 100644
--- a/app/services/post_status_service.rb
+++ b/app/services/post_status_service.rb
@@ -161,6 +161,7 @@ class PostStatusService < BaseService
 
   def validate_status!
     raise Mastodon::ValidationError, I18n.t('statuses.contains_ng_words') if Admin::NgWord.reject?("#{@options[:spoiler_text]}\n#{@options[:text]}")
+    raise Mastodon::ValidationError, I18n.t('statuses.too_many_hashtags') if Admin::NgWord.hashtag_reject_with_extractor?(@options[:text])
   end
 
   def validate_media!
diff --git a/app/services/update_status_service.rb b/app/services/update_status_service.rb
index 63f77cd753..be0bf526bc 100644
--- a/app/services/update_status_service.rb
+++ b/app/services/update_status_service.rb
@@ -75,6 +75,7 @@ class UpdateStatusService < BaseService
 
   def validate_status!
     raise Mastodon::ValidationError, I18n.t('statuses.contains_ng_words') if Admin::NgWord.reject?("#{@options[:spoiler_text]}\n#{@options[:text]}")
+    raise Mastodon::ValidationError, I18n.t('statuses.too_many_hashtags') if Admin::NgWord.hashtag_reject_with_extractor?(@options[:text])
   end
 
   def validate_media!
diff --git a/app/views/admin/ng_words/show.html.haml b/app/views/admin/ng_words/show.html.haml
index e8a87519c6..be8b56ac40 100644
--- a/app/views/admin/ng_words/show.html.haml
+++ b/app/views/admin/ng_words/show.html.haml
@@ -10,6 +10,9 @@
   .fields-group
     = f.input :ng_words, wrapper: :with_label, as: :text, input_html: { rows: 12 }, label: t('admin.ng_words.keywords')
 
+  .fields-group
+    = f.input :post_hash_tags_max, wrapper: :with_label, as: :integer, label: t('admin.ng_words.post_hash_tags_max')
+
   .fields-group
     = f.input :enable_block_emoji_reaction_settings, wrapper: :with_label, as: :boolean, label: t('admin.ng_words.enable_block_emoji_reaction_settings')
 
diff --git a/config/locales/en.yml b/config/locales/en.yml
index a70a11bf75..7da4133fbd 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -599,6 +599,7 @@ en:
       enable_block_emoji_reaction_settings: Enable block emoji reactions settings for users
       hide_local_users_for_anonymous: Hide timeline local user posts from anonymous
       keywords: Reject keywords
+      post_hash_tags_max: Hash tags max for posts
       title: NG words and against spams
     relationships:
       title: "%{acct}'s relationships"
@@ -1754,6 +1755,7 @@ en:
     show_thread: Show thread
     sign_in_to_participate: Login to participate in the conversation
     title: '%{name}: "%{quote}"'
+    too_many_hashtags: Too many hashtags
     visibilities:
       direct: Direct
       private: Followers-only
diff --git a/config/locales/ja.yml b/config/locales/ja.yml
index 49df945803..9eb9a9f3d2 100644
--- a/config/locales/ja.yml
+++ b/config/locales/ja.yml
@@ -598,6 +598,7 @@ ja:
       enable_block_emoji_reaction_settings: 各ユーザーにスタンプ機能のブロック設定項目を解放する
       hide_local_users_for_anonymous: ログインしていない状態でローカルユーザーの投稿をタイムラインから取得できないようにする
       keywords: 投稿できないキーワード
+      post_hash_tags_max: 投稿に設定可能なハッシュタグの最大数
       title: NGワードとスパム
     relationships:
       title: "%{acct} さんのフォロー・フォロワー"
@@ -1735,6 +1736,7 @@ ja:
     show_thread: スレッドを表示
     sign_in_to_participate: ログインして会話に参加
     title: '%{name}: "%{quote}"'
+    too_many_hashtags: ハッシュタグが多すぎます
     visibilities:
       direct: ダイレクト
       private: フォロワー限定