diff --git a/Gemfile b/Gemfile
index 7d680ba798a62..8289387e45f6d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -39,6 +39,8 @@ end
 
 gem 'net-ldap', '~> 0.17'
 gem 'omniauth-cas', '~> 2.0'
+gem 'omniauth-github', '~> 1.4'
+gem 'omniauth-gitlab', '~> 1.0.2'
 gem 'omniauth-saml', '~> 1.10'
 gem 'gitlab-omniauth-openid-connect', '~>0.10.0', require: 'omniauth_openid_connect'
 gem 'omniauth', '~> 1.9'
diff --git a/Gemfile.lock b/Gemfile.lock
index 3de14856da185..db7724a34af4c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -418,6 +418,7 @@ GEM
     minitest (5.16.3)
     msgpack (1.5.4)
     multi_json (1.15.0)
+    multi_xml (0.6.0)
     multipart-post (2.1.1)
     net-ldap (0.17.1)
     net-scp (4.0.0.rc1)
@@ -432,6 +433,12 @@ GEM
       concurrent-ruby (~> 1.0, >= 1.0.2)
       sidekiq (>= 3.5)
       statsd-ruby (~> 1.4, >= 1.4.0)
+    oauth2 (1.4.7)
+      faraday (>= 0.8, < 2.0)
+      jwt (>= 1.0, < 3.0)
+      multi_json (~> 1.3)
+      multi_xml (~> 0.5)
+      rack (>= 1.2, < 3)
     oj (3.13.21)
     omniauth (1.9.2)
       hashie (>= 3.4.6)
@@ -440,6 +447,15 @@ GEM
       addressable (~> 2.3)
       nokogiri (~> 1.5)
       omniauth (~> 1.2)
+    omniauth-github (1.4.0)
+      omniauth (~> 1.5)
+      omniauth-oauth2 (>= 1.4.0, < 2.0)
+    omniauth-gitlab (1.0.4)
+      omniauth (~> 1.0)
+      omniauth-oauth2 (~> 1.0)
+    omniauth-oauth2 (1.7.2)
+      oauth2 (~> 1.4)
+      omniauth (>= 1.9, < 3)
     omniauth-rails_csrf_protection (0.1.2)
       actionpack (>= 4.2)
       omniauth (>= 1.3.1)
@@ -819,6 +835,8 @@ DEPENDENCIES
   oj (~> 3.13)
   omniauth (~> 1.9)
   omniauth-cas (~> 2.0)
+  omniauth-github (~> 1.4)
+  omniauth-gitlab (~> 1.0.2)
   omniauth-rails_csrf_protection (~> 0.1)
   omniauth-saml (~> 1.10)
   ox (~> 2.14)
diff --git a/app/controllers/auth/omniauth_callbacks_controller.rb b/app/controllers/auth/omniauth_callbacks_controller.rb
index f9cf6d6551f68..5e6d8042071b1 100644
--- a/app/controllers/auth/omniauth_callbacks_controller.rb
+++ b/app/controllers/auth/omniauth_callbacks_controller.rb
@@ -7,6 +7,12 @@ def self.provides_callback_for(provider)
     define_method provider do
       @user = User.find_for_oauth(request.env['omniauth.auth'], current_user)
 
+      if @user.nil?
+        redirect_to new_user_registration_url
+        set_flash_message(:alert, 'should_register_before_auth_login', scope: 'devise.failure')
+        return
+      end
+
       if @user.persisted?
         LoginActivity.create(
           user: @user,
diff --git a/app/javascript/styles/mastodon/components.scss b/app/javascript/styles/mastodon/components.scss
index e47b1d0c01a0f..9d8d755cf9617 100644
--- a/app/javascript/styles/mastodon/components.scss
+++ b/app/javascript/styles/mastodon/components.scss
@@ -94,6 +94,19 @@
     outline: 0 !important;
   }
 
+  &.button-primary,
+  &.button-alternative,
+  &.button-secondary,
+  &.button-alternative-2,
+  &.button-github,
+  &.button-gitlab {
+    font-size: 16px;
+    line-height: 36px;
+    height: auto;
+    text-transform: none;
+    padding: 4px 16px;
+  }
+
   &.button-alternative {
     color: $inverted-text-color;
     background: $ui-primary-color;
@@ -154,6 +167,28 @@
     }
   }
 
+  &.button-github {
+    color: $white;
+    background: #24292f;
+
+    &:active,
+    &:focus,
+    &:hover {
+      background-color: lighten(#24292f, 4%);
+    }
+  }
+
+  &.button-gitlab {
+    color: $white;
+    background: #fc6d27;
+
+    &:active,
+    &:focus,
+    &:hover {
+      background-color: darken(#fc6d27, 4%);
+    }
+  }
+  
   &.button--block {
     display: block;
     width: 100%;
diff --git a/app/models/concerns/omniauthable.rb b/app/models/concerns/omniauthable.rb
index a90d5d888a5aa..5be9bde1ad65c 100644
--- a/app/models/concerns/omniauthable.rb
+++ b/app/models/concerns/omniauthable.rb
@@ -31,6 +31,8 @@ def find_for_oauth(auth, signed_in_resource = nil)
       user   = signed_in_resource || identity.user
       user ||= create_for_oauth(auth)
 
+      return nil if user.nil?
+
       if identity.user.nil?
         identity.user = user
         identity.save!
@@ -48,15 +50,18 @@ def create_for_oauth(auth)
       assume_verified   = strategy&.security&.assume_email_is_verified
       email_is_verified = auth.info.verified || auth.info.verified_email || auth.info.email_verified || assume_verified
       email             = auth.info.verified_email || auth.info.email
+      # email             = nil unless email_is_verified or trusted_auth_provider(auth)
 
-      user = User.find_by(email: email) if email_is_verified
+      user = User.find_by(email: email) if email_is_verified or trusted_auth_provider(auth)
 
       return user unless user.nil?
 
+      return nil if is_registration_limited
+
       user = User.new(user_params_from_auth(email, auth))
 
       user.account.avatar_remote_url = auth.info.image if /\A#{URI::DEFAULT_PARSER.make_regexp(%w(http https))}\z/.match?(auth.info.image)
-      user.skip_confirmation! if email_is_verified
+      user.skip_confirmation! if email_is_verified or trusted_auth_provider(auth)
       user.save!
       user
     end
@@ -69,19 +74,31 @@ def user_params_from_auth(email, auth)
         agreement: true,
         external: true,
         account_attributes: {
-          username: ensure_unique_username(ensure_valid_username(auth.uid)),
-          display_name: auth.info.full_name || auth.info.name || [auth.info.first_name, auth.info.last_name].join(' '),
+          username: ensure_unique_username(auth),
+          display_name: trusted_auth_provider_display_name(auth) || 
+                        auth.info.full_name || auth.info.name || [auth.info.first_name, auth.info.last_name].join(' '),
         },
       }
     end
 
-    def ensure_unique_username(starting_username)
-      username = starting_username
+    def ensure_unique_username(auth)
+      username = auth.uid
+      auth_provideded_username = nil
       i        = 0
 
+      if auth.provider == 'github'
+        auth_provideded_username = auth.info.nickname
+      elsif auth.provider == 'gitlab'
+        auth_provideded_username = auth.info.username
+      end
+
+      username = auth_provideded_username unless auth_provideded_username.empty?
+
+      username = ensure_valid_username(username)
+
       while Account.exists?(username: username, domain: nil)
         i       += 1
-        username = "#{starting_username}_#{i}"
+        username = "#{auth_provideded_username || auth.uid}_#{i}"
       end
 
       username
@@ -93,5 +110,29 @@ def ensure_valid_username(starting_username)
       validated_username = temp_username.truncate(30, omission: '')
       validated_username
     end
+    
+    def trusted_auth_provider(auth)
+      auth.provider == 'github' || auth.provider == 'gitlab'
+    end
+
+    def trusted_auth_provider_display_name(auth)
+      if auth.provider == 'github'
+        return auth.info.name
+      elsif auth.provider == 'gitlab'
+        return auth.info.name
+      end
+
+      return nil
+    end
+
+    def is_registration_limited()
+      if ENV['AUTO_REGISTRATION_WITH_AUTH_PROVIDERS'] == 'true'
+        return false
+      elsif Setting.registrations_mode != 'open'
+        return true
+      else
+        return false
+      end
+    end
   end
 end
diff --git a/config/initializers/omniauth.rb b/config/initializers/omniauth.rb
index f0167014676c9..9908b7d8e92d8 100644
--- a/config/initializers/omniauth.rb
+++ b/config/initializers/omniauth.rb
@@ -101,4 +101,14 @@
     oidc_options[:security][:assume_email_is_verified] = ENV['OIDC_SECURITY_ASSUME_EMAIL_IS_VERIFIED'] == 'true' #OPTIONAL
     config.omniauth :openid_connect, oidc_options
   end
+  
+  # Github strategy
+  if ENV['GITHUB_OAUTH2_ENABLED'] == 'true'
+    config.omniauth :github, ENV['GITHUB_OAUTH2_KEY'], ENV['GITHUB_OAUTH2_SECRET'], scope: 'user.info'
+  end
+
+  # Gitlab strategy
+  if ENV['GITLAB_OAUTH2_ENABLED'] == 'true'
+    config.omniauth :gitlab, ENV['GITLAB_OAUTH2_KEY'], ENV['GITLAB_OAUTH2_SECRET'], scope: 'read_user'
+  end
 end
diff --git a/config/locales/devise.en.yml b/config/locales/devise.en.yml
index 458fa6d7596e5..3b2ac750e7d76 100644
--- a/config/locales/devise.en.yml
+++ b/config/locales/devise.en.yml
@@ -16,6 +16,7 @@ en:
       timeout: Your session expired. Please sign in again to continue.
       unauthenticated: You need to sign in or sign up before continuing.
       unconfirmed: You have to confirm your email address before continuing.
+      should_register_before_auth_login: You need to sign up before continuing.
     mailer:
       confirmation_instructions:
         action: Verify email address
diff --git a/config/locales/devise.zh-CN.yml b/config/locales/devise.zh-CN.yml
index e2f7bafd1d107..aae09e9e0a4ba 100644
--- a/config/locales/devise.zh-CN.yml
+++ b/config/locales/devise.zh-CN.yml
@@ -16,6 +16,7 @@ zh-CN:
       timeout: 你的会话已过期。请重新登录再继续操作。
       unauthenticated: 继续操作前请注册或者登录。
       unconfirmed: 你必须先确认你的电子邮件地址才能继续。
+      should_register_before_auth_login: 请先注册。
     mailer:
       confirmation_instructions:
         action: 验证电子邮件地址
diff --git a/config/locales/devise.zh-HK.yml b/config/locales/devise.zh-HK.yml
index 2d9e8ddeada10..ef9aaac97b98a 100644
--- a/config/locales/devise.zh-HK.yml
+++ b/config/locales/devise.zh-HK.yml
@@ -16,6 +16,7 @@ zh-HK:
       timeout: 你的登入階段已經過期，請重新登入以繼續使用。
       unauthenticated: 你必須先登入或登記，以繼續使用。
       unconfirmed: 你必須先確認電郵地址，繼續使用。
+      should_register_before_auth_login: 你必須先登記，以繼續使用。
     mailer:
       confirmation_instructions:
         action: 驗證電子郵件地址
diff --git a/config/locales/devise.zh-TW.yml b/config/locales/devise.zh-TW.yml
index 0d9e6a56ad792..2b7cf9f9a867b 100644
--- a/config/locales/devise.zh-TW.yml
+++ b/config/locales/devise.zh-TW.yml
@@ -16,6 +16,7 @@ zh-TW:
       timeout: 登入階段逾時。請重新登入以繼續。
       unauthenticated: 您必須先登入或註冊才能繼續使用。
       unconfirmed: 您必須先確認電子信箱才能繼續使用。
+      should_register_before_auth_login: 您必須先註冊才能繼續使用。
     mailer:
       confirmation_instructions:
         action: 驗證電子信箱地址
diff --git a/config/locales/en.yml b/config/locales/en.yml
index a3046eb8ef827..4b3717efe587d 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1020,6 +1020,8 @@ en:
     providers:
       cas: CAS
       saml: SAML
+      github: GitHub
+      gitlab: GitLab
     register: Sign up
     registration_closed: "%{instance} is not accepting new members"
     resend_confirmation: Resend confirmation instructions