diff --git a/assets/javascripts/news.json b/assets/javascripts/news.json
index 68188b42..12d6569b 100644
--- a/assets/javascripts/news.json
+++ b/assets/javascripts/news.json
@@ -1,4 +1,8 @@
 [
+  [
+    "2020-12-23",
+    "New documentation: <a href=\"/gtk/\">GTK</a>"
+  ],
   [
     "2020-12-07",
     "New documentations: <a href=\"/flask/\">Flask</a>, <a href=\"/groovy/\">Groovy</a>, <a href=\"/jinja/\">Jinja</a>, <a href=\"/werkzeug/\">Werkzeug</a>"
diff --git a/assets/javascripts/templates/pages/about_tmpl.coffee b/assets/javascripts/templates/pages/about_tmpl.coffee
index 4405aa26..217bb32b 100644
--- a/assets/javascripts/templates/pages/about_tmpl.coffee
+++ b/assets/javascripts/templates/pages/about_tmpl.coffee
@@ -356,6 +356,11 @@ credits = [
     'GruntJS Team',
     'MIT',
     'https://github.com/gruntjs/grunt-docs/blob/master/package.json#L10'
+  ], [
+    'GTK',
+    'The GNOME Project',
+    'LGPLv2.1+',
+    'https://gitlab.gnome.org/GNOME/gtk/-/blob/master/COPYING'
   ], [
     'Handlebars',
     '2011-2017 Yehuda Katz',
diff --git a/assets/stylesheets/application.css.scss b/assets/stylesheets/application.css.scss
index 97347da6..fed660dc 100644
--- a/assets/stylesheets/application.css.scss
+++ b/assets/stylesheets/application.css.scss
@@ -59,10 +59,11 @@
         'pages/express',
         'pages/git',
         'pages/github',
+        'pages/gnuplot',
         'pages/go',
         'pages/graphite',
         'pages/groovy',
-        'pages/gnuplot',
+        'pages/gtk',
         'pages/haproxy',
         'pages/haskell',
         'pages/jekyll',
diff --git a/assets/stylesheets/pages/_gtk.scss b/assets/stylesheets/pages/_gtk.scss
new file mode 100644
index 00000000..9df0cd3e
--- /dev/null
+++ b/assets/stylesheets/pages/_gtk.scss
@@ -0,0 +1,15 @@
+._gtk {
+  padding-left: 1rem;
+
+  h1, h2, h3 { margin-left: -1rem; }
+  h2 { @extend %block-heading; }
+  h3 { @extend %block-label, %label-blue; }
+
+  div.toc { margin-top: 1.5em; }
+  .toc dl { margin-top: 0; margin-bottom: 0; }
+
+  .note { @extend %note, %note-green; }
+  .warning { @extend %note, %note-orange; }
+
+  .gallery-float { float:left; }
+}
diff --git a/docs/scraper-reference.md b/docs/scraper-reference.md
index c8ad24a4..fc00876d 100644
--- a/docs/scraper-reference.md
+++ b/docs/scraper-reference.md
@@ -190,6 +190,8 @@ More information about how filters work is available on the [Filter Reference](.
 In order to keep scrapers up-to-date the `get_latest_version(opts)` method should be overridden. If `self.release` is defined, this should return the latest version of the documentation. If `self.release` is not defined, it should return the Epoch time when the documentation was last modified. If the documentation will never change, simply return `1.0.0`. The result of this method is periodically reported in a "Documentation versions report" issue which helps maintainers keep track of outdated documentations.
 
 To make life easier, there are a few utility methods that you can use in `get_latest_version`:
+
+### General HTTP methods
 * `fetch(url, opts)`
 
   Makes a GET request to the url and returns the response body.
@@ -205,11 +207,15 @@ To make life easier, there are a few utility methods that you can use in `get_la
   Makes a GET request to the url and returns the JSON body converted to a dictionary.
 
   Example: [lib/docs/scrapers/mdn/mdn.rb](../lib/docs/scrapers/mdn/mdn.rb)
+
+### Package repository methods
 * `get_npm_version(package, opts)`
 
   Returns the latest version of the given npm package.
 
   Example: [lib/docs/scrapers/bower.rb](../lib/docs/scrapers/bower.rb)
+
+### GitHub methods
 * `get_latest_github_release(owner, repo, opts)`
 
   Returns the tag name of the latest GitHub release of the given repository. If the tag name is preceded by a "v", the "v" will be removed.
@@ -225,3 +231,15 @@ To make life easier, there are a few utility methods that you can use in `get_la
   Returns the contents of the requested file in the default branch of the given repository.
 
   Example: [lib/docs/scrapers/minitest.rb](../lib/docs/scrapers/minitest.rb)
+* `get_latest_github_commit_date(owner, repo, opts)`
+
+    Returns the date of the most recent commit in the default branch of the given repository.
+
+    Example: [lib/docs/scrapers/reactivex.rb](../lib/docs/scrapers/reactivex.rb)
+
+### GitLab methods
+* `get_gitlab_tags(hostname, group, project, opts)`
+
+  Returns the list of tags on the given repository ([format](https://docs.gitlab.com/ee/api/tags.html)).
+
+  Example: [lib/docs/scrapers/gtk.rb](../lib/docs/scrapers/gtk.rb)
diff --git a/lib/docs/core/doc.rb b/lib/docs/core/doc.rb
index 3b67acb1..979e2c41 100644
--- a/lib/docs/core/doc.rb
+++ b/lib/docs/core/doc.rb
@@ -270,5 +270,9 @@ module Docs
       timestamp = commits[0]['commit']['author']['date']
       Date.iso8601(timestamp).to_time.to_i
     end
+
+    def get_gitlab_tags(hostname, group, project, opts)
+      fetch_json("https://#{hostname}/api/v4/projects/#{group}%2F#{project}/repository/tags", opts)
+    end
   end
 end
diff --git a/lib/docs/filters/gtk/clean_html.rb b/lib/docs/filters/gtk/clean_html.rb
new file mode 100644
index 00000000..d093ef47
--- /dev/null
+++ b/lib/docs/filters/gtk/clean_html.rb
@@ -0,0 +1,69 @@
+module Docs
+  class Gtk
+    class CleanHtmlFilter < Filter
+      def call
+
+        css('table#top', 'table > colgroup', 'h2.title', '.footer', 'hr', 'br').remove
+
+        if root_page?
+          css('span > a').each do |node|
+            node.parent.before(node).remove
+          end
+        end
+
+        if top_table = at_css('.refnamediv > table')
+          top_table.css('td > p', 'td > img').each do |node|
+            top_table.before(node)
+          end
+          top_table.remove
+        end
+
+        css('table').each do |node|
+          node.remove_attribute 'border'
+          node.remove_attribute 'width'
+        end
+
+        # Move anchors to general headings
+        css('h2 > a[name]', 'h3 > a[name]').each do |node|
+          node.parent['id'] = node['name']
+        end
+
+        # Move anchors to function/struct/enum/etc.
+        css('a[name] + h2', 'a[name] + h3').each do |node|
+          node['id'] = node.previous_element['name']
+        end
+
+        # Move anchors to struct and enum members
+        css('td.struct_member_name', 'td.enum_member_name').each do |node|
+          node['id'] = node.at_css('a[name]')['name']
+        end
+
+        # Remove surrounding table from code blocks
+        css('.listing_frame').each do |node|
+          node.before(at_css('.listing_code')).remove
+        end
+
+        css('.literallayout code').each do |node|
+          node.name = 'pre'
+        end
+
+        # Fix code highlighting
+        css('pre').each do |node|
+          # If a codeblock has URLs, don't touch it
+          next if node.at_css('a[href]')
+
+          node.content = node.content
+
+          # it's not perfect, but make a guess at language
+          if node.content =~ /\<\?xml/
+            node['data-language'] = 'xml'
+          else
+            node['data-language'] = 'c'
+          end
+        end
+
+        doc
+      end
+    end
+  end
+end
diff --git a/lib/docs/filters/gtk/entries.rb b/lib/docs/filters/gtk/entries.rb
new file mode 100644
index 00000000..5cb3d27a
--- /dev/null
+++ b/lib/docs/filters/gtk/entries.rb
@@ -0,0 +1,154 @@
+module Docs
+  class Gtk
+    class EntriesFilter < Docs::EntriesFilter
+      # The GTK documentation paths are "flat" and while the contents of each
+      # page provides a way to determine the direct parent relationship, we
+      # really need a full hierarchy of pages *a priori* to be able to fully
+      # categorize all pages and entries. So we're going to recursivly generate
+      # a full map of page -> parent relationships from the table of contents...
+      PARENT_BY_PATH = {}
+
+      # And then use it to generate the list of 'breadcrumb' paths for each page
+      # ex: ['gtkwidgets', 'fancywidgets', 'gtkexamplewidget']
+      attr_accessor :breadcrumbs
+
+      # Map of paths to Page Names/Titles
+      NAME_BY_PATH = {}
+
+      # GTK+ 3 and GTK 4
+      REPLACE_NAMES = {
+        'I. GTK+ Overview' => '1. Overview',
+        'II. GTK+ Widgets and Objects' => '2. Widgets and Objects',
+        'III. GTK+ Core Reference' => '3. Core Reference',
+        'IV. Theming in GTK+' => '4. Theming',
+        'VI. GTK+ Tools' => '6. Tools',
+        'VII. GTK+ Platform Support' => '7. Platform Support',
+
+        'I. Introduction' => '1. Introduction',
+        'II. GTK Concepts' => '2. Concepts',
+        'III. GTK Widgets and Objects' => '3. Widgets and Objects',
+        'IV. GTK Core Reference' => '4. Core Reference',
+        'V. Theming in GTK' => '5. Theming',
+        'VII. GTK Tools' => '7. Tools',
+        'VIII. GTK Platform Support' => '8. Platform Support'
+      }
+
+      def call
+        if root_page?
+          # Generate NAME_BY_PATH Hash
+          css('dl.toc a').each do |node|
+            name = node.content
+            path = node['href'].split('/').last.remove('.html')
+            NAME_BY_PATH[path] = REPLACE_NAMES[name] || name
+          end
+          # Generate PARENT_BY_PATH Hash
+          process_toc(at_css('dl.toc'), nil)
+        end
+        super
+      end
+
+      # Recursive depth-first search
+      # Treat solo 'dt' nodes as leaf nodes and
+      # sibling 'dt + dd' nodes as nodes with children
+      def process_toc(toc_dl_node, parent_path)
+        toc_dl_node.css('> dt').each do |node|
+          node_path = node.at_css('a')['href'].split('/').last.remove('.html')
+          PARENT_BY_PATH[node_path] = parent_path
+
+          if node.next_element && node.next_element.name == 'dd'
+            children = node.next_element.children.first
+            process_toc(children, node_path)
+          end
+        end
+      end
+
+      def breadcrumbs
+        @breadcrumbs ||= get_breadcrumbs
+      end
+
+      def get_breadcrumbs
+        return [] if root_page?
+
+        breadcrumbs = []
+        path = slug.downcase
+        while path
+          breadcrumbs.prepend path
+          path = PARENT_BY_PATH[path]
+        end
+
+        breadcrumbs
+      end
+
+      def get_name
+        NAME_BY_PATH[self.breadcrumbs.last]
+      end
+
+      def get_type
+        NAME_BY_PATH[self.breadcrumbs.first]
+      end
+
+      def additional_entries
+        entries = []
+        type = case self.breadcrumbs.first
+        when 'gtkobjects'
+          "Widgets / #{NAME_BY_PATH[self.breadcrumbs[1]]}"
+        when 'gtkbase'
+          "Base / #{self.name}"
+        when'theming'
+          "Theming / #{self.name}"
+        end
+
+        if funcs = at_css('h2:contains("Functions")')
+          funcs.next_element.css('td.function_name > a').each do |node|
+            name = "#{node.content}()"
+            id = node['href']
+            entries << [name, id, type]
+          end
+        end
+
+        css('td.property_name > a').each do |node|
+          name = "#{node.content} (#{self.name} property)"
+          id = node['href']
+          entries << [name, id, type]
+        end
+
+        css('td.signal_name > a').each do |node|
+          name = "#{node.content} (#{self.name} signal)"
+          id = node['href']
+          entries << [name, id, type]
+        end
+
+        css('td.enum_member_name').each do |node|
+          name = node.content
+          id = node.at_css('a')['name']
+          entries << [name, id, type]
+        end
+
+        if values_node = at_css('h2:contains("Types and Values") + .informaltable')
+          values_node.css('tr').each do |node|
+            data_type = node.css('td').first.content
+            name = node.at_css('td.function_name').content
+            if data_type == ' '
+              name = "#{name} (type)"
+            elsif data_type == 'enum' || data_type == 'struct'
+              name = "#{name} (#{data_type})"
+            end
+            id = node.at_css('td.function_name a')['href']
+            entries << [name, id, type]
+          end
+        end
+
+        if slug == 'gtk-running'
+          css('h3 > a[name]').each do |node|
+            name = node.parent.content
+            id = node['name']
+            entries << [name, id, 'Platform / Environment Variables']
+          end
+        end
+
+        entries
+      end
+
+    end
+  end
+end
diff --git a/lib/docs/scrapers/gtk.rb b/lib/docs/scrapers/gtk.rb
new file mode 100644
index 00000000..cfa85956
--- /dev/null
+++ b/lib/docs/scrapers/gtk.rb
@@ -0,0 +1,116 @@
+module Docs
+  class Gtk < UrlScraper
+    self.name = 'GTK'
+    self.slug = 'gtk'
+    self.type = 'gtk'
+    self.root_path = 'index.html'
+    self.links = {
+      home: 'https://www.gtk.org/',
+      code: 'https://gitlab.gnome.org/GNOME/gtk/'
+    }
+
+    html_filters.push 'gtk/entries', 'gtk/clean_html', 'title'
+
+    options[:container] = '.content'
+
+    # These are all "index"-ish pages with no valuable content
+    GTK3_SKIP = %w(
+      gtk.html
+        gtk-resources.html gtk-question-index.html
+      gtkobjects.html
+        Application.html Builder.html WindowWidgets.html LayoutContainers.html
+        DisplayWidgets.html ButtonWidgets.html NumericEntry.html
+        TextWidgetObjects.html TreeWidgetObjects.html MenusAndCombos.html
+        SelectorWidgets.html Ornaments.html ScrollingWidgets.html Printing.html
+        ShortcutsOverview.html MiscObjects.html AbstractObjects.html
+        PlugSocket.html RecentDocuments.html ApplicationChoosing.html
+        Gestures.html DeprecatedObjects.html
+      gtkbase.html
+      theming.html
+      migrating.html
+        ch26s02.html ch28s02.html
+      pt06.html
+      platform-support.html
+      glossary.html
+      annotation-glossary.html
+    )
+
+    GTK3_SKIP_PATTERNS = [
+      /migrating/, /checklist/, /ch30/, /ch32/, /api-index-/
+    ]
+
+    # These are all "index"-ish pages with no valuable content
+    GTK4_SKIP = %w(
+      gtk.html
+        gtk-resources.html gtk-question-index.html ch02s02.html
+      concepts.html
+      gtkobjects.html
+        Lists.html Trees.html Application.html Builder.html WindowWidgets.html
+        LayoutContainers.html LayoutManagers.html DisplayWidgets.html
+        MediaSupport.html ButtonWidgets.html NumericEntry.html
+        MenusAndCombos.html SelectorWidgets.html DrawingWidgets.html
+        Ornaments.html ScrollingWidgets.html Printing.html
+        ShortcutsOverview.html MiscObjects.html AbstractObjects.html
+        RecentDocuments.html ApplicationChoosing.html Gestures.html ch36.html
+        ch37.html
+      gtkbase.html
+      theming.html
+      migrating.html
+        ch41s02.html ch41s03.html
+      pt07.html
+      platform-support.html
+      api-index-full.html
+      annotation-glossary.html
+    )
+
+    GTK4_SKIP_PATTERNS = [
+      /migrating/, /ch03/, /ch09/, /ch10/
+    ]
+
+    options[:attribution] = <<-HTML
+      &copy; 2005&ndash;2020 The GNOME Project<br>
+      Licensed under the GNU Lesser General Public License version 2.1 or later.
+    HTML
+
+    version '4.0' do
+      self.release = '4.0.0'
+      self.base_url = "https://developer.gnome.org/gtk4/#{self.version}/"
+
+      options[:root_title] = 'GTK 4 Reference Manual'
+      options[:skip] = GTK4_SKIP
+      options[:skip_patterns] = GTK4_SKIP_PATTERNS
+    end
+
+    version '3.24' do
+      self.release = '3.24.24'
+      self.base_url = "https://developer.gnome.org/gtk3/#{self.version}/"
+
+      options[:root_title] = 'GTK+ 3 Reference Manual'
+      options[:skip] = GTK3_SKIP
+      options[:skip_patterns] = GTK3_SKIP_PATTERNS
+    end
+
+    version '3.22' do
+      self.release = '3.22.3'
+      self.base_url = "https://developer.gnome.org/gtk3/#{self.version}/"
+
+      options[:root_title] = 'GTK+ 3 Reference Manual'
+      options[:skip] = GTK3_SKIP
+      options[:skip_patterns] = GTK3_SKIP_PATTERNS
+    end
+
+    version '3.20' do
+      self.release = '3.20.4'
+      self.base_url = "https://developer.gnome.org/gtk3/#{self.version}/"
+
+      options[:root_title] = 'GTK+ 3 Reference Manual'
+      options[:skip] = GTK3_SKIP
+      options[:skip_patterns] = GTK3_SKIP_PATTERNS
+    end
+
+    def get_latest_version(opts)
+      tags = get_gitlab_tags('gitlab.gnome.org', 'GNOME', 'gtk', opts)
+      tags[0]['name']
+    end
+  end
+end
diff --git a/public/icons/docs/gtk/16.png b/public/icons/docs/gtk/16.png
new file mode 100644
index 00000000..d3a7e72a
Binary files /dev/null and b/public/icons/docs/gtk/16.png differ
diff --git a/public/icons/docs/gtk/16@2x.png b/public/icons/docs/gtk/16@2x.png
new file mode 100644
index 00000000..dd3482d6
Binary files /dev/null and b/public/icons/docs/gtk/16@2x.png differ
diff --git a/public/icons/docs/gtk/SOURCE b/public/icons/docs/gtk/SOURCE
new file mode 100644
index 00000000..a18c5432
--- /dev/null
+++ b/public/icons/docs/gtk/SOURCE
@@ -0,0 +1 @@
+https://www.gtk.org/assets/img/logo-gtk-sm.png