diff --git a/app/assets/javascripts/admin/templates/group.hbs b/app/assets/javascripts/admin/templates/group.hbs
index 03d9d697e67..ac76d7056ad 100644
--- a/app/assets/javascripts/admin/templates/group.hbs
+++ b/app/assets/javascripts/admin/templates/group.hbs
@@ -43,6 +43,17 @@
     {{combo-box name="alias" valueAttribute="value" value=alias_level content=aliasLevelOptions}}
   </div>
 
+  {{#unless automatic}}
+    <div>
+      <label for="automatic_membership">{{i18n 'admin.groups.automatic_membership_email_domains'}}</label>
+      {{list-setting name="automatic_membership" settingValue=automatic_membership_email_domains}}
+      <label>
+        {{input type="checkbox" checked=automatic_membership_retroactive}}
+        {{i18n 'admin.groups.automatic_membership_retroactive'}}
+      </label>
+    </div>
+  {{/unless}}
+
   <div class='buttons'>
     <button {{action "save"}} {{bind-attr disabled="disableSave"}} class='btn btn-primary'>{{i18n 'admin.customize.save'}}</button>
     {{#unless automatic}}
diff --git a/app/assets/javascripts/discourse/models/group.js b/app/assets/javascripts/discourse/models/group.js
index c492cce5455..a598b9822b4 100644
--- a/app/assets/javascripts/discourse/models/group.js
+++ b/app/assets/javascripts/discourse/models/group.js
@@ -68,7 +68,9 @@ Discourse.Group = Discourse.Model.extend({
     return {
       name: this.get('name'),
       alias_level: this.get('alias_level'),
-      visible: !!this.get('visible')
+      visible: !!this.get('visible'),
+      automatic_membership_email_domains: this.get('automatic_membership_email_domains'),
+      automatic_membership_retroactive: !!this.get('automatic_membership_retroactive')
     };
   },
 
diff --git a/app/assets/stylesheets/common/admin/admin_base.scss b/app/assets/stylesheets/common/admin/admin_base.scss
index dca9a5403bf..33ce6d2ef9a 100644
--- a/app/assets/stylesheets/common/admin/admin_base.scss
+++ b/app/assets/stylesheets/common/admin/admin_base.scss
@@ -463,6 +463,7 @@ section.details {
 .groups {
   .ac-wrap {
     width: 100% !important;
+    border-color: scale-color($primary, $lightness: 75%);
     .item {
       width: 190px;
       margin-right: 0 !important;
@@ -480,6 +481,13 @@ section.details {
   .controls {
     margin-top: 10px;
   }
+  .select2-container {
+    width: 100%;
+  }
+  .select2-choices {
+    width: 100%;
+    border-color: scale-color($primary, $lightness: 75%);
+  }
 }
 
 // Customise area
diff --git a/app/controllers/admin/groups_controller.rb b/app/controllers/admin/groups_controller.rb
index 0cdf0413691..65b737392ea 100644
--- a/app/controllers/admin/groups_controller.rb
+++ b/app/controllers/admin/groups_controller.rb
@@ -21,8 +21,11 @@ class Admin::GroupsController < Admin::AdminController
 
   def create
     group = Group.new
+
     group.name = (params[:name] || '').strip
     group.visible = params[:visible] == "true"
+    group.automatic_membership_email_domains = params[:automatic_membership_email_domains]
+    group.automatic_membership_retroactive = params[:automatic_membership_retroactive] == "true"
 
     if group.save
       render_serialized(group, BasicGroupSerializer)
@@ -36,11 +39,13 @@ class Admin::GroupsController < Admin::AdminController
 
     group.alias_level = params[:alias_level].to_i if params[:alias_level].present?
     group.visible = params[:visible] == "true"
+    group.automatic_membership_email_domains = params[:automatic_membership_email_domains]
+    group.automatic_membership_retroactive = params[:automatic_membership_retroactive] == "true"
     # group rename is ignored for automatic groups
     group.name = params[:name] if params[:name] && !group.automatic
 
     if group.save
-      render json: success_json
+      render_serialized(group, BasicGroupSerializer)
     else
       render_json_error group
     end
diff --git a/app/jobs/regular/automatic_group_membership.rb b/app/jobs/regular/automatic_group_membership.rb
new file mode 100644
index 00000000000..d49d5b37989
--- /dev/null
+++ b/app/jobs/regular/automatic_group_membership.rb
@@ -0,0 +1,23 @@
+module Jobs
+
+  class AutomaticGroupMembership < Jobs::Base
+
+    def execute(args)
+      group_id = args[:group_id]
+
+      raise Discourse::InvalidParameters.new(:group_id) if group_id.blank?
+
+      group = Group.find(group_id)
+
+      return unless group.automatic_membership_retroactive
+
+      domains = group.automatic_membership_email_domains.gsub('.', '\.')
+
+      User.where("email ~* '@(#{domains})'").find_each do |user|
+        group.add(user) rescue ActiveRecord::RecordNotUnique
+      end
+    end
+
+  end
+
+end
diff --git a/app/models/group.rb b/app/models/group.rb
index d9985367df1..33ed718aed6 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -11,6 +11,7 @@ class Group < ActiveRecord::Base
   has_many :managers, through: :group_managers
 
   after_save :destroy_deletions
+  after_save :automatic_group_membership
 
   validate :name_format_validator
   validates_uniqueness_of :name, case_sensitive: false
@@ -301,6 +302,12 @@ class Group < ActiveRecord::Base
       @deletions = nil
     end
 
+    def automatic_group_membership
+      if self.automatic_membership_retroactive
+        Jobs.enqueue(:automatic_group_membership, group_id: self.id)
+      end
+    end
+
 end
 
 # == Schema Information
diff --git a/app/models/user.rb b/app/models/user.rb
index 8b597298f6c..64e9749bed8 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -79,6 +79,7 @@ class User < ActiveRecord::Base
   after_create :create_user_stat
   after_create :create_user_profile
   after_create :ensure_in_trust_level_group
+  after_create :automatic_group_membership
 
   before_save :update_username_lower
   before_save :ensure_password_is_hashed
@@ -715,6 +716,17 @@ class User < ActiveRecord::Base
     Group.user_trust_level_change!(id, trust_level)
   end
 
+  def automatic_group_membership
+    Group.where(automatic: false)
+         .where("LENGTH(COALESCE(automatic_membership_email_domains, '')) > 0")
+         .each do |group|
+      domains = group.automatic_membership_email_domains.gsub('.', '\.')
+      if self.email =~ Regexp.new("@(#{domains})", true)
+        group.add(self) rescue ActiveRecord::RecordNotUnique
+      end
+    end
+  end
+
   def create_user_stat
     stat = UserStat.new(new_since: Time.now)
     stat.user_id = id
diff --git a/app/serializers/basic_group_serializer.rb b/app/serializers/basic_group_serializer.rb
index 8f1574cb97b..2bf2d111be6 100644
--- a/app/serializers/basic_group_serializer.rb
+++ b/app/serializers/basic_group_serializer.rb
@@ -1,3 +1,14 @@
 class BasicGroupSerializer < ApplicationSerializer
-  attributes :id, :automatic, :name, :user_count, :alias_level, :visible
+  attributes :id,
+             :automatic,
+             :name,
+             :user_count,
+             :alias_level,
+             :visible,
+             :automatic_membership_email_domains,
+             :automatic_membership_retroactive
+
+  def automatic_membership_email_domains
+    object.automatic_membership_email_domains.presence || ""
+  end
 end
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index d24229b9cbc..3c37e443d23 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -1633,6 +1633,8 @@ en:
         add_members: "Add members"
         custom: "Custom"
         automatic: "Automatic"
+        automatic_membership_email_domains: "Users registering with an email from that list will automatically be a member of this group"
+        automatic_membership_retroactive: "Registered users matching this list are also member of the group"
 
       api:
         generate_master: "Generate Master API Key"
diff --git a/db/migrate/20150123145128_add_automatic_membership_to_group.rb b/db/migrate/20150123145128_add_automatic_membership_to_group.rb
new file mode 100644
index 00000000000..2ea654656e2
--- /dev/null
+++ b/db/migrate/20150123145128_add_automatic_membership_to_group.rb
@@ -0,0 +1,6 @@
+class AddAutomaticMembershipToGroup < ActiveRecord::Migration
+  def change
+    add_column :groups, :automatic_membership_email_domains, :text
+    add_column :groups, :automatic_membership_retroactive, :boolean, default: false
+  end
+end
diff --git a/spec/controllers/admin/groups_controller_spec.rb b/spec/controllers/admin/groups_controller_spec.rb
index 8c83768e0d5..8efd09bd5ed 100644
--- a/spec/controllers/admin/groups_controller_spec.rb
+++ b/spec/controllers/admin/groups_controller_spec.rb
@@ -25,7 +25,9 @@ describe Admin::GroupsController do
         "user_count"=>1,
         "automatic"=>false,
         "alias_level"=>0,
-        "visible"=>true
+        "visible"=>true,
+        "automatic_membership_email_domains"=>"",
+        "automatic_membership_retroactive"=>false
       }])
     end
 
@@ -57,6 +59,18 @@ describe Admin::GroupsController do
       expect(group.visible).to eq(true)
     end
 
+    it "doesn't launch the 'automatic group membership' job when it's not retroactive" do
+      Jobs.expects(:enqueue).never
+      xhr :put, :update, id: 1, automatic_membership_retroactive: "false"
+      expect(response).to be_success
+    end
+
+    it "launches the 'automatic group membership' job when it's retroactive" do
+      Jobs.expects(:enqueue).with(:automatic_group_membership, group_id: 1)
+      xhr :put, :update, id: 1, automatic_membership_retroactive: "true"
+      expect(response).to be_success
+    end
+
   end
 
   context ".destroy" do
diff --git a/spec/jobs/automatic_group_membership_spec.rb b/spec/jobs/automatic_group_membership_spec.rb
new file mode 100644
index 00000000000..fe80c04cae2
--- /dev/null
+++ b/spec/jobs/automatic_group_membership_spec.rb
@@ -0,0 +1,22 @@
+require 'spec_helper'
+require_dependency 'jobs/regular/automatic_group_membership'
+
+describe Jobs::AutomaticGroupMembership do
+
+  it "raises an error when the group id is missing" do
+    expect { Jobs::AutomaticGroupMembership.new.execute({}) }.to raise_error(Discourse::InvalidParameters)
+  end
+
+  it "updates the membership" do
+    user1 = Fabricate(:user, email: "foo@wat.com")
+    user2 = Fabricate(:user, email: "foo@bar.com")
+    group = Fabricate(:group, automatic_membership_email_domains: "wat.com", automatic_membership_retroactive: true)
+
+    Jobs::AutomaticGroupMembership.new.execute(group_id: group.id)
+
+    group.reload
+    expect(group.users.include?(user1)).to eq(true)
+    expect(group.users.include?(user2)).to eq(false)
+  end
+
+end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 96aa8286c59..b918d44467e 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -1213,4 +1213,15 @@ describe User do
 
   end
 
+  describe "automatic group membership" do
+
+    it "is automatically added to a group when the email matches" do
+      group = Fabricate(:group, automatic_membership_email_domains: "bar.com|wat.com")
+      user = Fabricate(:user, email: "foo@bar.com")
+      group.reload
+      expect(group.users.include?(user)).to eq(true)
+    end
+
+  end
+
 end