diff --git a/app/controllers/categories_controller.rb b/app/controllers/categories_controller.rb
index c1446481308..3fb80f71aef 100644
--- a/app/controllers/categories_controller.rb
+++ b/app/controllers/categories_controller.rb
@@ -138,6 +138,7 @@ class CategoriesController < ApplicationController
                         :logo_url,
                         :background_url,
                         :allow_badges,
+                        :slug,
                         :permissions => [*p.try(:keys)])
       end
     end
diff --git a/app/models/category.rb b/app/models/category.rb
index 846f5b36b15..0680ca96a05 100644
--- a/app/models/category.rb
+++ b/app/models/category.rb
@@ -32,7 +32,9 @@ class Category < ActiveRecord::Base
                    length: { in: 1..50 }
   validate :parent_category_validator
 
-  before_validation :ensure_slug
+  # before_validation :ensure_slug
+  # before_save :ensure_slug
+  validate :ensure_slug
   before_save :apply_permissions
   before_save :downcase_email
   before_save :downcase_name
@@ -196,18 +198,23 @@ SQL
 
   end
 
+  def duplicate_slug?
+    Category.where(slug: self.slug, parent_category_id: parent_category_id).where.not(id: id).any?
+  end
+
   def ensure_slug
     if name.present?
       self.name.strip!
-      self.slug = Slug.for(name)
 
-      return if self.slug.blank?
-
-      # If a category with that slug already exists, set the slug to nil so the category can be found
-      # another way.
-      category = Category.where(slug: self.slug, parent_category_id: parent_category_id)
-      category = category.where("id != ?", id) if id.present?
-      self.slug = '' if category.exists?
+      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
     end
   end
 
diff --git a/spec/controllers/categories_controller_spec.rb b/spec/controllers/categories_controller_spec.rb
index 08b731d6df0..9131980c1b6 100644
--- a/spec/controllers/categories_controller_spec.rb
+++ b/spec/controllers/categories_controller_spec.rb
@@ -43,13 +43,12 @@ describe CategoriesController do
         end
       end
 
-
       describe "success" do
         it "works" do
           readonly = CategoryGroup.permission_types[:readonly]
           create_post = CategoryGroup.permission_types[:create_post]
 
-          xhr :post, :create, name: "hello", color: "ff0", text_color: "fff",
+          xhr :post, :create, name: "hello", color: "ff0", text_color: "fff", slug: "hello-cat",
                               auto_close_hours: 72,
                               permissions: {
                                 "everyone" => readonly,
@@ -62,6 +61,7 @@ describe CategoriesController do
             [Group[:everyone].id, readonly],[Group[:staff].id,create_post]
           ]
           category.name.should == "hello"
+          category.slug.should == "hello-cat"
           category.color.should == "ff0"
           category.auto_close_hours.should == 72
         end
@@ -180,7 +180,7 @@ describe CategoriesController do
           readonly = CategoryGroup.permission_types[:readonly]
           create_post = CategoryGroup.permission_types[:create_post]
 
-          xhr :put, :update, id: @category.id, name: "hello", color: "ff0", text_color: "fff",
+          xhr :put, :update, id: @category.id, name: "hello", color: "ff0", text_color: "fff", slug: "hello-category",
                               auto_close_hours: 72,
                               permissions: {
                                 "everyone" => readonly,
@@ -193,6 +193,7 @@ describe CategoriesController do
             [Group[:everyone].id, readonly],[Group[:staff].id,create_post]
           ]
           @category.name.should == "hello"
+          @category.slug.should == "hello-category"
           @category.color.should == "ff0"
           @category.auto_close_hours.should == 72
         end
diff --git a/spec/models/category_spec.rb b/spec/models/category_spec.rb
index 6defee8fee6..9e3cf3d0fd0 100644
--- a/spec/models/category_spec.rb
+++ b/spec/models/category_spec.rb
@@ -192,6 +192,20 @@ describe Category do
     end
   end
 
+  describe 'custom slug can be provided' do
+    it 'has the custom value' do
+      c = Fabricate(:category, name: "Cats", slug: "cats-category")
+      c.slug.should eq("cats-category")
+    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")
+      c2.should_not be_valid
+      c2.errors[:slug].should be_present
+    end
+  end
+
   describe 'description_text' do
     it 'correctly generates text description as needed' do
       c = Category.new
@@ -284,6 +298,16 @@ describe Category do
     end
   end
 
+  describe "update" do
+    it "should enforce uniqueness of slug" do
+      Fabricate(:category, slug: "the-slug")
+      c2 = Fabricate(:category, slug: "different-slug")
+      c2.slug = "the-slug"
+      c2.should_not be_valid
+      c2.errors[:slug].should be_present
+    end
+  end
+
   describe 'destroy' do
     before do
       @category = Fabricate(:category)