diff --git a/app/assets/javascripts/discourse/controllers/edit-category.js.es6 b/app/assets/javascripts/discourse/controllers/edit-category.js.es6
index 7f0f6654959..443d3bcb7c4 100644
--- a/app/assets/javascripts/discourse/controllers/edit-category.js.es6
+++ b/app/assets/javascripts/discourse/controllers/edit-category.js.es6
@@ -146,9 +146,9 @@ export default ObjectController.extend(ModalFunctionality, {
 
       }).catch(function(error) {
         if (error && error.responseText) {
-          self.flash($.parseJSON(error.responseText).errors[0]);
+          self.flash($.parseJSON(error.responseText).errors[0], 'error');
         } else {
-          self.flash(I18n.t('generic_error'));
+          self.flash(I18n.t('generic_error'), 'error');
         }
         self.set('saving', false);
       });
diff --git a/app/assets/javascripts/discourse/models/category.js b/app/assets/javascripts/discourse/models/category.js
index 3f0732328fe..3f8bb6edb67 100644
--- a/app/assets/javascripts/discourse/models/category.js
+++ b/app/assets/javascripts/discourse/models/category.js
@@ -58,6 +58,7 @@ Discourse.Category = Discourse.Model.extend({
     return Discourse.ajax(url, {
       data: {
         name: this.get('name'),
+        slug: this.get('slug'),
         color: this.get('color'),
         text_color: this.get('text_color'),
         secure: this.get('secure'),
diff --git a/app/assets/javascripts/discourse/templates/modal/edit-category-general.hbs b/app/assets/javascripts/discourse/templates/modal/edit-category-general.hbs
index 096441c01a2..7931c5ef57e 100644
--- a/app/assets/javascripts/discourse/templates/modal/edit-category-general.hbs
+++ b/app/assets/javascripts/discourse/templates/modal/edit-category-general.hbs
@@ -1,7 +1,13 @@
 <form>
   <section class='field'>
-    <label>{{i18n 'category.name'}}</label>
-    {{text-field value=name placeholderKey="category.name_placeholder" maxlength="50"}}
+    <section class="field-item">
+      <label>{{i18n 'category.name'}}</label>
+      {{text-field value=name placeholderKey="category.name_placeholder" maxlength="50"}}
+    </section>
+    <section class="field-item">
+      <label>{{i18n 'category.slug'}}</label>
+      {{text-field value=slug placeholderKey="category.slug_placeholder" maxlength="255"}}
+    </section>
   </section>
 
   {{#if canSelectParentCategory}}
diff --git a/app/assets/stylesheets/common/base/modal.scss b/app/assets/stylesheets/common/base/modal.scss
index 8e35ab13b62..bc77284478b 100644
--- a/app/assets/stylesheets/common/base/modal.scss
+++ b/app/assets/stylesheets/common/base/modal.scss
@@ -130,6 +130,10 @@
   section.field {
     margin-bottom: 20px;
   }
+  section.field .field-item {
+    display: inline-block;
+    margin-right: 10px;
+  }
 }
 
 .reply-where-modal {
diff --git a/app/controllers/categories_controller.rb b/app/controllers/categories_controller.rb
index 3fb80f71aef..a97f7ff7706 100644
--- a/app/controllers/categories_controller.rb
+++ b/app/controllers/categories_controller.rb
@@ -95,6 +95,19 @@ class CategoriesController < ApplicationController
     end
   end
 
+  def update_slug
+    @category = Category.find(params[:category_id].to_i)
+    guardian.ensure_can_edit!(@category)
+
+    custom_slug = params[:slug].to_s
+
+    if custom_slug.present? && @category.update_attributes(slug: custom_slug)
+      render json: success_json
+    else
+      render_json_error(@category)
+    end
+  end
+
   def set_notifications
     category_id = params[:category_id].to_i
     notification_level = params[:notification_level].to_i
diff --git a/app/models/category.rb b/app/models/category.rb
index 4103eb86974..3535019b76b 100644
--- a/app/models/category.rb
+++ b/app/models/category.rb
@@ -201,18 +201,19 @@ SQL
   end
 
   def ensure_slug
-    if name.present?
-      self.name.strip!
+    return unless name.present?
 
-      if slug.present?
-        # custom slug
-        errors.add(:slug, "is already in use") if duplicate_slug?
-      else
-        # auto slug
-        self.slug = Slug.for(name)
-        return if self.slug.blank?
-        self.slug = '' if duplicate_slug?
-      end
+    self.name.strip!
+
+    if slug.present?
+      # santized custom slug
+      self.slug = Slug.for(slug)
+      errors.add(:slug, 'is already in use') if duplicate_slug?
+    else
+      # auto slug
+      self.slug = Slug.for(name)
+      return if self.slug.blank?
+      self.slug = '' if duplicate_slug?
     end
   end
 
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index 294010a1cc2..5186255fe70 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -1281,6 +1281,8 @@ en:
       delete: 'Delete Category'
       create: 'New Category'
       save: 'Save Category'
+      slug: 'Category Slug'
+      slug_placeholder: '(Optional) dashed-words for url'
       creation_error: There has been an error during the creation of the category.
       save_error: There was an error saving the category.
       name: "Category Name"
diff --git a/config/routes.rb b/config/routes.rb
index 81a8d29efe1..0c883317bdd 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -325,6 +325,7 @@ Discourse::Application.routes.draw do
   post "category/uploads" => "categories#upload"
   post "category/:category_id/move" => "categories#move"
   post "category/:category_id/notifications" => "categories#set_notifications"
+  put "category/:category_id/slug" => "categories#update_slug"
 
   get "c/:id/show" => "categories#show"
   get "c/:category.rss" => "list#category_feed", format: :rss
diff --git a/spec/controllers/categories_controller_spec.rb b/spec/controllers/categories_controller_spec.rb
index 9131980c1b6..0dd227c4b1b 100644
--- a/spec/controllers/categories_controller_spec.rb
+++ b/spec/controllers/categories_controller_spec.rb
@@ -203,4 +203,42 @@ describe CategoriesController do
 
   end
 
+  describe 'update_slug' do
+    it 'requires the user to be logged in' do
+      lambda { xhr :put, :update_slug, category_id: 'category'}.should raise_error(Discourse::NotLoggedIn)
+    end
+
+    describe 'logged in' do
+      let(:valid_attrs) { {id: @category.id, slug: 'fff'} }
+
+      before do
+        @user = log_in(:admin)
+        @category = Fabricate(:happy_category, user: @user)
+      end
+
+      it 'rejects blank' do
+        xhr :put, :update_slug, category_id: @category.id, slug: nil
+        response.status.should == 422
+      end
+
+      it 'accepts valid custom slug' do
+        xhr :put, :update_slug, category_id: @category.id, slug: 'valid-slug'
+        response.should be_success
+        category = Category.find(@category.id)
+        category.slug.should == 'valid-slug'
+      end
+
+      it 'accepts not well formed custom slug' do
+        xhr :put, :update_slug, category_id: @category.id, slug: ' valid slug'
+        response.should be_success
+        category = Category.find(@category.id)
+        category.slug.should == 'valid-slug'
+      end
+
+      it 'rejects invalid custom slug' do
+        xhr :put, :update_slug, category_id: @category.id, slug: '  '
+        response.status.should == 422
+      end
+    end
+  end
 end
diff --git a/spec/fabricators/category_fabricator.rb b/spec/fabricators/category_fabricator.rb
index dae13377459..1f237b5d684 100644
--- a/spec/fabricators/category_fabricator.rb
+++ b/spec/fabricators/category_fabricator.rb
@@ -7,3 +7,9 @@ Fabricator(:diff_category, from: :category) do
   name "Different Category"
   user
 end
+
+Fabricator(:happy_category, from: :category) do
+  name 'Happy Category'
+  slug 'happy'
+  user
+end
diff --git a/spec/models/category_spec.rb b/spec/models/category_spec.rb
index 9e3cf3d0fd0..93b3cf5ec63 100644
--- a/spec/models/category_spec.rb
+++ b/spec/models/category_spec.rb
@@ -198,6 +198,11 @@ describe Category do
       c.slug.should eq("cats-category")
     end
 
+    it 'and be sanitized' do
+      c = Fabricate(:category, name: 'Cats', slug: '  invalid slug')
+      c.slug.should == 'invalid-slug'
+    end
+
     it 'fails if custom slug is duplicate with existing' do
       c1 = Fabricate(:category, name: "Cats", slug: "cats")
       c2 = Fabricate.build(:category, name: "More Cats", slug: "cats")