diff --git a/lib/rouge/lexers/gdt.rb b/lib/rouge/lexers/gdt.rb
new file mode 100644
index 0000000000..3cffc3ade1
--- /dev/null
+++ b/lib/rouge/lexers/gdt.rb
@@ -0,0 +1,41 @@
+# -*- coding: utf-8 -*- #
+# frozen_string_literal: true
+
+module Rouge
+  module Lexers
+    class GDT < RegexLexer
+      title 'GDT'
+      desc "Geräte-Daten-Träger (Device Data Carrier)"
+      tag 'gdt'
+      filenames '*.gdt'
+      mimetypes 'text/x-gdt'
+
+      state :root do
+        rule %r/[0-9]{3}/, Text, :length
+      end
+
+      state :length do
+        rule %r/(6227|6228)/, Keyword, :comment
+        rule %r/8000/, Keyword, :type
+        rule %r/[0-9]{4}/, Keyword, :content
+        rule %r/\s+/, Text::Whitespace
+      end
+
+      state :content do
+        rule %r(.*?$), Literal, :root
+      end
+
+      state :comment do
+        rule %r(.*?$), Comment, :root
+      end
+
+      state :type do
+        rule %r(.*?$), Name::Class, :root
+      end
+
+      state :whitespace do
+        rule %r/\s+/, Text::Whitespace
+      end
+    end
+  end
+end
diff --git a/spec/lexers/gdt_spec.rb b/spec/lexers/gdt_spec.rb
new file mode 100644
index 0000000000..d23508c296
--- /dev/null
+++ b/spec/lexers/gdt_spec.rb
@@ -0,0 +1,18 @@
+# -*- coding: utf-8 -*- #
+# frozen_string_literal: true
+
+describe Rouge::Lexers::GDT do
+  let(:subject) { Rouge::Lexers::GDT.new }
+
+  describe 'guessing' do
+    include Support::Guessing
+
+    it 'guesses by filename' do
+      assert_guess :filename => 'foo.gdt'
+    end
+
+    it 'guesses by mimetype' do
+      assert_guess :mimetype => 'text/x-gdt'
+    end
+  end
+end