diff --git a/Gemfile b/Gemfile
index af82ae16a56a40aabf58160ffdd3ccb54a137b7c..78748d0e9f870bb8dbc61fa7c0ddae36d92eeb4c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -104,7 +104,7 @@ gem 'deckar01-task_list', '1.0.5', require: 'task_list/railtie'
 gem 'gitlab-markup',      '~> 1.5.0'
 gem 'redcarpet',          '~> 3.3.3'
 gem 'RedCloth',           '~> 4.3.2'
-gem 'rdoc',               '~>3.6'
+gem 'rdoc',               '~> 4.2'
 gem 'org-ruby',           '~> 0.9.12'
 gem 'creole',             '~> 0.5.0'
 gem 'wikicloth',          '0.8.1'
@@ -260,9 +260,6 @@ group :development do
   gem 'better_errors', '~> 1.0.1'
   gem 'binding_of_caller', '~> 0.7.2'
 
-  # Docs generator
-  gem 'sdoc', '~> 0.3.20'
-
   # thin instead webrick
   gem 'thin', '~> 1.7.0'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 888fa6b2bf5ca6d3abfdbc9835b6c5d0b5f87cd2..3ecff5f6a6856e7de91dcad268fa42842d45fd29 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -567,7 +567,7 @@ GEM
       ffi (>= 0.5.0)
     rblineprof (0.3.6)
       debugger-ruby_core_source (~> 1.3)
-    rdoc (3.12.2)
+    rdoc (4.2.2)
       json (~> 1.4)
     recaptcha (3.0.0)
       json
@@ -663,9 +663,6 @@ GEM
     scss_lint (0.47.1)
       rake (>= 0.9, < 11)
       sass (~> 3.4.15)
-    sdoc (0.3.20)
-      json (>= 1.1.3)
-      rdoc (~> 3.10)
     seed-fu (2.3.6)
       activerecord (>= 3.1)
       activesupport (>= 3.1)
@@ -936,7 +933,7 @@ DEPENDENCIES
   rails-deprecated_sanitizer (~> 1.0.3)
   rainbow (~> 2.1.0)
   rblineprof (~> 0.3.6)
-  rdoc (~> 3.6)
+  rdoc (~> 4.2)
   recaptcha (~> 3.0)
   redcarpet (~> 3.3.3)
   redis (~> 3.2)
@@ -956,7 +953,6 @@ DEPENDENCIES
   sanitize (~> 2.0)
   sass-rails (~> 5.0.6)
   scss_lint (~> 0.47.0)
-  sdoc (~> 0.3.20)
   seed-fu (~> 2.3.5)
   select2-rails (~> 3.5.9)
   sentry-raven (~> 2.0.0)
diff --git a/doc/development/rake_tasks.md b/doc/development/rake_tasks.md
index a7175f3f87e708b836c626ddfe5e93214a7be3d2..827db7e99b88cdf6fabeb3b709ad87eeac631773 100644
--- a/doc/development/rake_tasks.md
+++ b/doc/development/rake_tasks.md
@@ -42,14 +42,6 @@ To run several tests inside one directory:
 If you want to use [Spring](https://github.com/rails/spring) set
 `ENABLE_SPRING=1` in your environment.
 
-## Generate searchable docs for source code
-
-You can find results under the `doc/code` directory.
-
-```
-bundle exec rake gitlab:generate_docs
-```
-
 ## Generate API documentation for project services (e.g. Slack)
 
 ```
diff --git a/lib/tasks/gitlab/generate_docs.rake b/lib/tasks/gitlab/generate_docs.rake
deleted file mode 100644
index f6448c38e1006b2d7c3c320070d579e68ee59259..0000000000000000000000000000000000000000
--- a/lib/tasks/gitlab/generate_docs.rake
+++ /dev/null
@@ -1,7 +0,0 @@
-namespace :gitlab do
-  desc "GitLab | Generate sdocs for project"
-  task generate_docs: :environment do
-    system(*%W(bundle exec sdoc -o doc/code app lib))
-  end
-end
-