diff --git a/app/logical/source/extractor.rb b/app/logical/source/extractor.rb
index e79daa769..f720e6a01 100644
--- a/app/logical/source/extractor.rb
+++ b/app/logical/source/extractor.rb
@@ -39,6 +39,7 @@ module Source
       Source::Extractor::Moebooru,
       Source::Extractor::Nijie,
       Source::Extractor::ArtStation,
+      Source::Extractor::Gelbooru,
       Source::Extractor::HentaiFoundry,
       Source::Extractor::Fanbox,
       Source::Extractor::Mastodon,
diff --git a/app/logical/source/extractor/gelbooru.rb b/app/logical/source/extractor/gelbooru.rb
new file mode 100644
index 000000000..b3d1717ac
--- /dev/null
+++ b/app/logical/source/extractor/gelbooru.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+# Source extractor for Gelbooru. The commentary and artist information are
+# pulled from the Gelbooru post's source, while the translated tags include
+# both the Gelbooru tags and the source's tags.
+#
+# @see Source::URL::Gelbooru
+# @see https://gelbooru.com/index.php?page=wiki&s=view&id=18780 (howto:api)
+module Source
+  class Extractor
+    class Gelbooru < Source::Extractor
+      delegate :artist_name, :profile_url, :profile_urls, :other_names, :tag_name, :artist_commentary_title, :artist_commentary_desc, :dtext_artist_commentary_title, :dtext_artist_commentary_desc, to: :sub_extractor, allow_nil: true
+
+      def match?
+        Source::URL::Gelbooru === parsed_url
+      end
+
+      def image_urls
+        [api_response[:file_url]].compact
+      end
+
+      def page_url
+        "https://gelbooru.com/index.php?page=post&s=view&id=#{post_id}" if post_id.present?
+      end
+
+      def tags
+        gelbooru_tags + source_tags
+      end
+
+      def gelbooru_tags
+        return [] if api_response.nil?
+
+        tags = api_response[:tags].split + ["rating:#{api_response[:rating]}"]
+        tags.map do |tag|
+          [tag, "https://gelbooru.com/index.php?page=post&s=list&tags=#{CGI.escape(tag)}"]
+        end
+      end
+
+      def source_tags
+        sub_extractor&.tags.to_a
+      end
+
+      def post_id
+        parsed_url.post_id || parsed_referer&.post_id || post_id_from_md5
+      end
+
+      def api_url
+        # https://gelbooru.com/index.php?page=dapi&s=post&q=index&id=779812&json=1
+        "https://gelbooru.com/index.php?page=dapi&s=post&q=index&id=#{post_id}&json=1" if post_id.present?
+      end
+
+      memoize def api_response
+        return nil unless api_url.present?
+
+        response = http.cache(1.minute).get(api_url)
+        return nil unless response.status == 200
+
+        response.parse["post"].first.with_indifferent_access
+      end
+
+      memoize def post_id_from_md5
+        return nil unless parsed_url.image_url? && parsed_url.page_url.present?
+
+        response = http.cache(1.minute).head(parsed_url.page_url)
+        return nil unless response.status == 200
+
+        Source::URL.parse(response.uri).post_id
+      end
+
+      def sub_extractor
+        return nil if api_response[:source].nil?
+        @sub_extractor ||= Source::Extractor.find(api_response[:source], default: nil)
+      end
+    end
+  end
+end
diff --git a/app/logical/source/url.rb b/app/logical/source/url.rb
index 4cac2fd7e..e9c48ca00 100644
--- a/app/logical/source/url.rb
+++ b/app/logical/source/url.rb
@@ -40,6 +40,7 @@ module Source
       Source::URL::Fantia,
       Source::URL::Fc2,
       Source::URL::Foundation,
+      Source::URL::Gelbooru,
       Source::URL::HentaiFoundry,
       Source::URL::Instagram,
       Source::URL::Lofter,
diff --git a/app/logical/source/url/gelbooru.rb b/app/logical/source/url/gelbooru.rb
new file mode 100644
index 000000000..8c9e7f6a8
--- /dev/null
+++ b/app/logical/source/url/gelbooru.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+class Source::URL::Gelbooru < Source::URL
+  attr_reader :post_id, :md5, :full_image_url
+
+  def self.match?(url)
+    url.domain.in?(%w[gelbooru.com])
+  end
+
+  def parse
+    case [domain, *path_segments]
+
+    # https://gelbooru.com/index.php?page=post&s=view&id=7798045
+    # https://www.gelbooru.com/index.php?page=post&s=view&id=7798045
+    in "gelbooru.com", "index.php" if params[:page] == "post" && params[:s] == "view" && params[:id].present?
+      @post_id = params[:id].to_i
+
+    # https://gelbooru.com/index.php?page=post&s=list&md5=99d9977d6c3aa185083a2da22bd8acfb
+    in "gelbooru.com", "index.php" if params[:page] == "post" && params[:s] == "list" && params[:md5].present?
+      @md5 = params[:md5]
+
+    # https://gelbooru.com/index.php?page=dapi&s=post&q=index&id=7798045&json=1
+    in "gelbooru.com", "index.php" if params[:page] == "dapi" && params[:q] == "index" && params[:id].present?
+      @post_id = params[:id].to_i
+
+    # https://gelbooru.com//images/ee/5c/ee5c9a69db9602c95debdb9b98fb3e3e.jpeg
+    # http://simg.gelbooru.com//images/2003/edd1d2b3881cf70c3acf540780507531.png
+    # https://simg3.gelbooru.com//samples/0b/3a/sample_0b3ae5e225072b8e391c827cb470d29c.jpg
+    # https://video-cdn3.gelbooru.com/images/62/95/6295154d082f04009160261b90e7176e.mp4
+    # https://img2.gelbooru.com//images/a9/64/a96478bbf9bc3f0584f2b5ddf56025fa.webm
+    # https://gelbooru.com/thumbnails/08/06/thumbnail_08066c138e7e138a47489a0934c29156.jpg
+    in "gelbooru.com", ("images" | "samples" | "thumbnails"), h1, h2, /\A(?:\w+_)?(\h{32})\.(jpeg|jpg|png|gif|mp4|webm)\z/i
+      @md5 = $1
+      @full_image_url = "https://#{host}/images/#{h1}/#{h2}/#{md5}.#{file_ext}"
+
+    else
+      nil
+    end
+  end
+
+  def image_url?
+    full_image_url.present?
+  end
+
+  def page_url
+    if post_id.present?
+      "https://gelbooru.com/index.php?page=post&s=view&id=#{post_id}"
+    elsif md5.present?
+      "https://gelbooru.com/index.php?page=post&s=list&md5=#{md5}"
+    end
+  end
+
+  def api_url
+    "https://gelbooru.com/index.php?page=dapi&s=post&q=index&id=#{post_id}&json=1" if post_id.present?
+  end
+end
diff --git a/app/logical/source/url/null.rb b/app/logical/source/url/null.rb
index 92ddd4ec4..9ded3f6d0 100644
--- a/app/logical/source/url/null.rb
+++ b/app/logical/source/url/null.rb
@@ -131,15 +131,6 @@ class Source::URL::Null < Source::URL
       @work_id = $1
       @page_url = "https://www.facebook.com/photo.php?fbid=#{work_id}"
 
-    # https://gelbooru.com//images/ee/5c/ee5c9a69db9602c95debdb9b98fb3e3e.jpeg
-    # http://simg.gelbooru.com//images/2003/edd1d2b3881cf70c3acf540780507531.png
-    # https://simg3.gelbooru.com//samples/0b/3a/sample_0b3ae5e225072b8e391c827cb470d29c.jpg
-    # https://video-cdn3.gelbooru.com/images/62/95/6295154d082f04009160261b90e7176e.mp4
-    # https://img2.gelbooru.com//images/a9/64/a96478bbf9bc3f0584f2b5ddf56025fa.webm
-    in _, "gelbooru.com", ("images" | "samples"), *subdirs, /^(?:sample_)?(\h{32})\.(jpeg|jpg|png|gif|mp4|webm)$/
-      @md5 = $1
-      @page_url = "https://gelbooru.com/index.php?page=post&s=list&tags=md5:#{@md5}"
-
     # https://a.hitomi.la/galleries/907838/1.png
     # https://0a.hitomi.la/galleries/1169701/23.png
     # https://aa.hitomi.la/galleries/990722/003_01_002.jpg
diff --git a/test/functional/uploads_controller_test.rb b/test/functional/uploads_controller_test.rb
index c75aa2926..11ad1860b 100644
--- a/test/functional/uploads_controller_test.rb
+++ b/test/functional/uploads_controller_test.rb
@@ -313,6 +313,8 @@ class UploadsControllerTest < ActionDispatch::IntegrationTest
         should_upload_successfully("https://konachan.com/post/show/270916")
         should_upload_successfully("https://konachan.com/image/ca12cdb79a66d242e95a6f958341bf05/Konachan.com%20-%20270916.png")
 
+        should_upload_successfully("https://gelbooru.com/index.php?page=post&s=view&id=7798121")
+
         should_upload_successfully("http://lohas.nicoseiga.jp/o/910aecf08e542285862954017f8a33a8c32a8aec/1433298801/4937663")
         should_upload_successfully("http://seiga.nicovideo.jp/seiga/im4937663")
         should_upload_successfully("https://seiga.nicovideo.jp/image/source/9146749")
diff --git a/test/unit/sources/gelbooru_test.rb b/test/unit/sources/gelbooru_test.rb
new file mode 100644
index 000000000..128514dad
--- /dev/null
+++ b/test/unit/sources/gelbooru_test.rb
@@ -0,0 +1,58 @@
+require "test_helper"
+
+module Sources
+  class GelbooruTest < ActiveSupport::TestCase
+    context "A Gelbooru direct image url without a referer" do
+      strategy_should_work(
+        "https://img3.gelbooru.com/images/04/f2/04f2767c64593c3030ce74ecc2528704.jpg",
+        image_urls: ["https://img3.gelbooru.com/images/04/f2/04f2767c64593c3030ce74ecc2528704.jpg"],
+        artist_name: "灰色灰烬bot",
+        profile_url: "https://www.pixiv.net/users/3330425",
+        tags: %w[1girl back_bow bangs black_pantyhose blue_bow blue_hair blue_ribbon boots bow cape chibi chinese_commentary closed_eyes full_body hair_between_eyes hair_ribbon hat hatsune_miku indai_(3330425) on_ground pantyhose pom_pom_(clothes) rabbit rabbit_yukine rating:general ribbon simple_background sitting solo twintails vocaloid white_background white_cape white_headwear witch_hat yuki_miku yuki_miku_(2014) 初音ミク 雪ミク],
+        artist_commentary_title: "2010~2021雪ミク",
+        artist_commentary_desc: "动作参考@速写班长",
+        download_size: 480_621,
+      )
+    end
+
+    context "A Gelbooru direct image url with a referer" do
+      strategy_should_work(
+        "https://img3.gelbooru.com/images/04/f2/04f2767c64593c3030ce74ecc2528704.jpg",
+        referer: "https://gelbooru.com/index.php?page=post&s=view&id=7798121",
+        image_urls: ["https://img3.gelbooru.com/images/04/f2/04f2767c64593c3030ce74ecc2528704.jpg"],
+        artist_name: "灰色灰烬bot",
+        profile_url: "https://www.pixiv.net/users/3330425",
+        tags: %w[1girl back_bow bangs black_pantyhose blue_bow blue_hair blue_ribbon boots bow cape chibi chinese_commentary closed_eyes full_body hair_between_eyes hair_ribbon hat hatsune_miku indai_(3330425) on_ground pantyhose pom_pom_(clothes) rabbit rabbit_yukine rating:general ribbon simple_background sitting solo twintails vocaloid white_background white_cape white_headwear witch_hat yuki_miku yuki_miku_(2014) 初音ミク 雪ミク],
+        artist_commentary_title: "2010~2021雪ミク",
+        artist_commentary_desc: "动作参考@速写班长",
+        download_size: 480_621,
+      )
+    end
+
+    context "A Gelbooru sample image url" do
+      strategy_should_work(
+        "https://img3.gelbooru.com/samples/04/f2/sample_04f2767c64593c3030ce74ecc2528704.jpg",
+        image_urls: ["https://img3.gelbooru.com/images/04/f2/04f2767c64593c3030ce74ecc2528704.jpg"],
+        artist_name: "灰色灰烬bot",
+        profile_url: "https://www.pixiv.net/users/3330425",
+        tags: %w[1girl back_bow bangs black_pantyhose blue_bow blue_hair blue_ribbon boots bow cape chibi chinese_commentary closed_eyes full_body hair_between_eyes hair_ribbon hat hatsune_miku indai_(3330425) on_ground pantyhose pom_pom_(clothes) rabbit rabbit_yukine rating:general ribbon simple_background sitting solo twintails vocaloid white_background white_cape white_headwear witch_hat yuki_miku yuki_miku_(2014) 初音ミク 雪ミク],
+        artist_commentary_title: "2010~2021雪ミク",
+        artist_commentary_desc: "动作参考@速写班长",
+        download_size: 480_621,
+      )
+    end
+
+    context "A Gelbooru page url" do
+      strategy_should_work(
+        "https://gelbooru.com/index.php?page=post&s=view&id=7798121",
+        image_urls: ["https://img3.gelbooru.com/images/04/f2/04f2767c64593c3030ce74ecc2528704.jpg"],
+        artist_name: "灰色灰烬bot",
+        profile_url: "https://www.pixiv.net/users/3330425",
+        tags: %w[1girl back_bow bangs black_pantyhose blue_bow blue_hair blue_ribbon boots bow cape chibi chinese_commentary closed_eyes full_body hair_between_eyes hair_ribbon hat hatsune_miku indai_(3330425) on_ground pantyhose pom_pom_(clothes) rabbit rabbit_yukine rating:general ribbon simple_background sitting solo twintails vocaloid white_background white_cape white_headwear witch_hat yuki_miku yuki_miku_(2014) 初音ミク 雪ミク],
+        artist_commentary_title: "2010~2021雪ミク",
+        artist_commentary_desc: "动作参考@速写班长",
+        download_size: 480_621,
+      )
+    end
+  end
+end