diff --git a/CHANGELOG_KB.md b/CHANGELOG_KB.md
index 8247373a16..37c59ee93a 100644
--- a/CHANGELOG_KB.md
+++ b/CHANGELOG_KB.md
@@ -4,6 +4,7 @@
 
 ### 追加
 
+- カスタム絵文字の`isSensitive`値のサポート (from Misskey)
 - カスタム絵文字の検索用のエイリアスキーワード
 - アンテナの STL（ソーシャルタイムライン）モード
 - アカウントの投稿数、フォロー数、フォロワー数の隠蔽
diff --git a/app/javascript/mastodon/actions/importer/normalizer.js b/app/javascript/mastodon/actions/importer/normalizer.js
index b030c94b31..fc279fbca5 100644
--- a/app/javascript/mastodon/actions/importer/normalizer.js
+++ b/app/javascript/mastodon/actions/importer/normalizer.js
@@ -91,6 +91,11 @@ export function normalizeStatus(status, normalOldStatus) {
       normalStatus.spoiler_text = '';
     }
 
+    console.dir(normalStatus.emojis);
+    if (normalStatus.emojis && normalStatus.emojis.some((emoji) => emoji.is_sensitive) && !normalStatus.spoiler_text) {
+      normalStatus.spoiler_text = '[Contains sensitive custom emoji(s)]';
+    }
+
     const spoilerText   = normalStatus.spoiler_text || '';
     const searchContent = ([spoilerText, status.content].concat((status.poll && status.poll.options) ? status.poll.options.map(option => option.title) : [])).concat(status.media_attachments.map(att => att.description)).join('\n\n').replace(/<br\s*\/?>/g, '\n').replace(/<\/p><p>/g, '\n\n');
     const emojiMap      = makeEmojiMap(normalStatus);
diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 689372987b..2b64b9524d 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -263,7 +263,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     return unless emoji.nil? || custom_emoji_parser.image_remote_url != emoji.image_remote_url || (custom_emoji_parser.updated_at && custom_emoji_parser.updated_at >= emoji.updated_at)
 
     begin
-      emoji ||= CustomEmoji.new(domain: @account.domain, shortcode: custom_emoji_parser.shortcode, uri: custom_emoji_parser.uri)
+      emoji ||= CustomEmoji.new(domain: @account.domain, shortcode: custom_emoji_parser.shortcode, uri: custom_emoji_parser.uri, is_sensitive: custom_emoji_parser.is_sensitive)
       emoji.image_remote_url = custom_emoji_parser.image_remote_url
       emoji.save
     rescue Seahorse::Client::NetworkingError => e
diff --git a/app/lib/activitypub/parser/custom_emoji_parser.rb b/app/lib/activitypub/parser/custom_emoji_parser.rb
index 724c602150..25feb3cf11 100644
--- a/app/lib/activitypub/parser/custom_emoji_parser.rb
+++ b/app/lib/activitypub/parser/custom_emoji_parser.rb
@@ -24,4 +24,8 @@ class ActivityPub::Parser::CustomEmojiParser
   rescue ArgumentError
     nil
   end
+
+  def is_sensitive # rubocop:disable Naming/PredicateName
+    (@json['isSensitive'].presence || false)
+  end
 end
diff --git a/app/models/custom_emoji.rb b/app/models/custom_emoji.rb
index 4855c188dc..f74e034503 100644
--- a/app/models/custom_emoji.rb
+++ b/app/models/custom_emoji.rb
@@ -22,6 +22,7 @@
 #  image_width                  :integer
 #  image_height                 :integer
 #  aliases                      :jsonb
+#  is_sensitive                 :boolean          default(FALSE), not null
 #
 
 class CustomEmoji < ApplicationRecord
diff --git a/app/serializers/rest/custom_emoji_serializer.rb b/app/serializers/rest/custom_emoji_serializer.rb
index 27795f2a38..465979184f 100644
--- a/app/serializers/rest/custom_emoji_serializer.rb
+++ b/app/serializers/rest/custom_emoji_serializer.rb
@@ -3,7 +3,7 @@
 class REST::CustomEmojiSerializer < ActiveModel::Serializer
   include RoutingHelper
 
-  attributes :shortcode, :url, :static_url, :visible_in_picker
+  attributes :shortcode, :url, :static_url, :visible_in_picker, :is_sensitive
 
   attribute :category, if: :category_loaded?
   attribute :width, if: :width?
diff --git a/db/migrate/20230522082252_add_is_sensitive_to_custom_emojis.rb b/db/migrate/20230522082252_add_is_sensitive_to_custom_emojis.rb
new file mode 100644
index 0000000000..12666eec39
--- /dev/null
+++ b/db/migrate/20230522082252_add_is_sensitive_to_custom_emojis.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddIsSensitiveToCustomEmojis < ActiveRecord::Migration[6.1]
+  def change
+    add_column :custom_emojis, :is_sensitive, :boolean, null: false, default: false
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index e931742255..b362bdd571 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -12,7 +12,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2023_05_21_122642) do
+ActiveRecord::Schema.define(version: 2023_05_22_082252) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -439,6 +439,7 @@ ActiveRecord::Schema.define(version: 2023_05_21_122642) do
     t.integer "image_width"
     t.integer "image_height"
     t.jsonb "aliases"
+    t.boolean "is_sensitive", default: false, null: false
     t.index ["shortcode", "domain"], name: "index_custom_emojis_on_shortcode_and_domain", unique: true
   end
 
@@ -1488,4 +1489,4 @@ ActiveRecord::Schema.define(version: 2023_05_21_122642) do
 
 end
 
-#rubocop:enable all
+# rubocop:enable all