diff --git a/app/assets/javascripts/discourse/components/number-field.js.es6 b/app/assets/javascripts/discourse/components/number-field.js.es6
new file mode 100644
index 00000000000..5104138c08e
--- /dev/null
+++ b/app/assets/javascripts/discourse/components/number-field.js.es6
@@ -0,0 +1,29 @@
+import computed from 'ember-addons/ember-computed-decorators';
+
+export default Ember.TextField.extend({
+
+  classNameBindings: ['invalid'],
+
+  @computed('number')
+  value: {
+    get(number) {
+      return parseInt(number);
+    },
+    set(value) {
+      const num = parseInt(value);
+      if (isNaN(num)) {
+        this.set('invalid', true);
+        return value;
+      } else {
+        this.set('invalid', false);
+        this.set('number', num);
+        return num.toString();
+      }
+    }
+  },
+
+  @computed("placeholderKey")
+  placeholder(key) {
+    return key ? I18n.t(key) : "";
+  }
+});
diff --git a/app/assets/javascripts/discourse/controllers/reorder-categories.js.es6 b/app/assets/javascripts/discourse/controllers/reorder-categories.js.es6
new file mode 100644
index 00000000000..0c7ab22caed
--- /dev/null
+++ b/app/assets/javascripts/discourse/controllers/reorder-categories.js.es6
@@ -0,0 +1,95 @@
+import ModalFunctionality from 'discourse/mixins/modal-functionality';
+const BufferedProxy = window.BufferedProxy; // import BufferedProxy from 'ember-buffered-proxy/proxy';
+import binarySearch from 'discourse/lib/binary-search';
+import { popupAjaxError } from 'discourse/lib/ajax-error';
+import computed from "ember-addons/ember-computed-decorators";
+import Ember from 'ember';
+
+export default Ember.Controller.extend(ModalFunctionality, Ember.Evented, {
+
+  @computed("site.categories")
+  categoriesBuffered(categories) {
+    const bufProxy = Ember.ObjectProxy.extend(BufferedProxy);
+    return categories.map(c => bufProxy.create({ content: c }));
+  },
+
+  // uses propertyDidChange()
+  @computed('categoriesBuffered')
+  categoriesGrouped(cats) {
+    const map = {};
+    cats.forEach((cat) => {
+      const p = cat.get('position') || 0;
+      if (!map[p]) {
+        map[p] = {pos: p, cats: [cat]};
+      } else {
+        map[p].cats.push(cat);
+      }
+    });
+    const result = [];
+    Object.keys(map).map(p => parseInt(p)).sort((a,b) => a-b).forEach(function(pos) {
+      result.push(map[pos]);
+    });
+    return result;
+  },
+
+  showApplyAll: function() {
+    let anyChanged = false;
+    this.get('categoriesBuffered').forEach(bc => { anyChanged = anyChanged || bc.get('hasBufferedChanges') });
+    return anyChanged;
+  }.property('categoriesBuffered.@each.hasBufferedChanges'),
+
+  saveDisabled: Ember.computed.alias('showApplyAll'),
+
+  moveDir(cat, dir) {
+    const grouped = this.get('categoriesGrouped'),
+      curPos = cat.get('position'),
+      curGroupIdx = binarySearch(grouped, curPos, "pos"),
+      curGroup = grouped[curGroupIdx];
+
+    if (curGroup.cats.length === 1 && ((dir === -1 && curGroupIdx !== 0) || (dir === 1 && curGroupIdx !== (grouped.length - 1)))) {
+      const nextGroup = grouped[curGroupIdx + dir],
+        nextPos = nextGroup.pos;
+      cat.set('position', nextPos);
+    } else {
+      cat.set('position', curPos + dir);
+    }
+    cat.applyBufferedChanges();
+    Ember.run.next(this, () => {
+      this.propertyDidChange('categoriesGrouped');
+      Ember.run.schedule('afterRender', this, () => {
+        this.set('scrollIntoViewId', cat.get('id'));
+        this.trigger('scrollIntoView');
+      });
+    });
+  },
+
+  actions: {
+
+    moveUp(cat) {
+      this.moveDir(cat, -1);
+    },
+    moveDown(cat) {
+      this.moveDir(cat, 1);
+    },
+
+    commit() {
+      this.get('categoriesBuffered').forEach(bc => {
+        if (bc.get('hasBufferedChanges')) {
+          bc.applyBufferedChanges();
+        }
+      });
+      this.propertyDidChange('categoriesGrouped');
+    },
+
+    saveOrder() {
+      const data = {};
+      this.get('categoriesBuffered').forEach((cat) => {
+        data[cat.get('id')] = cat.get('position');
+      });
+      Discourse.ajax('/categories/reorder',
+        {type: 'POST', data: {mapping: JSON.stringify(data)}}).
+        then(() => this.send("closeModal")).
+        catch(popupAjaxError);
+    }
+  }
+});
diff --git a/app/assets/javascripts/discourse/lib/binary-search.js.es6 b/app/assets/javascripts/discourse/lib/binary-search.js.es6
new file mode 100644
index 00000000000..03675866e0a
--- /dev/null
+++ b/app/assets/javascripts/discourse/lib/binary-search.js.es6
@@ -0,0 +1,29 @@
+// The binarySearch() function is licensed under the UNLICENSE
+// https://github.com/Olical/binary-search
+
+// Modified for use in Discourse
+
+export default function binarySearch(list, target, keyProp) {
+  var min = 0;
+  var max = list.length - 1;
+  var guess;
+  var keyProperty = keyProp || "id";
+
+  while (min <= max) {
+    guess = Math.floor((min + max) / 2);
+
+    if (Em.get(list[guess], keyProperty) === target) {
+      return guess;
+    }
+    else {
+      if (Em.get(list[guess], keyProperty) < target) {
+        min = guess + 1;
+      }
+      else {
+        max = guess - 1;
+      }
+    }
+  }
+
+  return -Math.floor((min + max) / 2);
+}
diff --git a/app/assets/javascripts/discourse/routes/discovery-categories.js.es6 b/app/assets/javascripts/discourse/routes/discovery-categories.js.es6
index d8a34f06253..297fc1ac1ee 100644
--- a/app/assets/javascripts/discourse/routes/discovery-categories.js.es6
+++ b/app/assets/javascripts/discourse/routes/discovery-categories.js.es6
@@ -56,6 +56,10 @@ const DiscoveryCategoriesRoute = Discourse.Route.extend(OpenComposer, {
       this.controllerFor("editCategory").set("selectedTab", "general");
     },
 
+    reorderCategories() {
+      showModal("reorderCategories");
+    },
+
     createTopic() {
       this.openComposer(this.controllerFor("discovery/categories"));
     },
diff --git a/app/assets/javascripts/discourse/templates/modal/reorder-categories.hbs b/app/assets/javascripts/discourse/templates/modal/reorder-categories.hbs
new file mode 100644
index 00000000000..7a5b3172b66
--- /dev/null
+++ b/app/assets/javascripts/discourse/templates/modal/reorder-categories.hbs
@@ -0,0 +1,36 @@
+<div>
+  <div class="modal-body reorder-categories">
+    <div id="rc-scroll-anchor"></div>
+    <table>
+      <thead>
+      <th class="th-pos">Position</th>
+      <th class="th-cat">Category</th>
+      </thead>
+      {{#each categoriesGrouped as |group|}}
+        <tbody>
+        {{#each group.cats as |cat|}}
+          <tr data-category-id="{{cat.id}}">
+            <td>
+              {{number-field number=cat.position}}
+              {{d-button class="no-text" action="moveUp" actionParam=cat icon="arrow-up"}}
+              {{d-button class="no-text" action="moveDown" actionParam=cat icon="arrow-down"}}
+              {{#if cat.hasBufferedChanges}}
+                {{d-button class="no-text" action="commit" icon="check"}}
+              {{/if}}
+            </td>
+            <td>{{category-badge cat allowUncategorized="true"}}</td>
+          </tr>
+        {{/each}}
+        </tbody>
+      {{/each}}
+    </table>
+    <div id="rc-scroll-bottom"></div>
+  </div>
+
+  <div class="modal-footer">
+    {{#if showApplyAll}}
+      {{d-button action="commit" icon="check" label="categories.reorder.apply_all"}}
+    {{/if}}
+    {{d-button class="btn-primary" disabled=saveDisabled action="saveOrder" label="categories.reorder.save"}}
+  </div>
+</div>
diff --git a/app/assets/javascripts/discourse/templates/navigation/categories.hbs b/app/assets/javascripts/discourse/templates/navigation/categories.hbs
index 6ba5509e9bb..c6b4c1cbbc9 100644
--- a/app/assets/javascripts/discourse/templates/navigation/categories.hbs
+++ b/app/assets/javascripts/discourse/templates/navigation/categories.hbs
@@ -3,7 +3,10 @@
 {{navigation-bar navItems=navItems filterMode=filterMode}}
 
 {{#if canCreateCategory}}
-  <button class='btn btn-default' {{action "createCategory"}}><i class='fa fa-plus'></i>{{i18n 'category.create'}}</button>
+  {{d-button action="createCategory" icon="plus" label="category.create"}}
+  {{#if siteSettings.fixed_category_positions}}
+    {{d-button action="reorderCategories" icon="random" label="category.reorder"}}
+  {{/if}}
 {{/if}}
 {{#if canCreateTopic}}
   <button id="create-topic" class='btn btn-default' {{action "createTopic"}}><i class='fa fa-plus'></i>{{i18n 'topic.create'}}</button>
diff --git a/app/assets/javascripts/discourse/views/reorder-categories.js.es6 b/app/assets/javascripts/discourse/views/reorder-categories.js.es6
new file mode 100644
index 00000000000..570c9ec9637
--- /dev/null
+++ b/app/assets/javascripts/discourse/views/reorder-categories.js.es6
@@ -0,0 +1,80 @@
+import ModalBodyView from "discourse/views/modal-body";
+
+export default ModalBodyView.extend({
+  title: I18n.t('categories.reorder.title'),
+  templateName: 'modal/reorder-categories',
+
+  _setup: function() {
+    this.get('controller').on('scrollIntoView', this, this.scrollIntoView);
+  }.on('didInsertElement'),
+  _teardown: function() {
+    this.get('controller').off('scrollIntoView', this, this.scrollIntoView);
+    this.set('prevScrollElem', null);
+  }.on('willClearRender'),
+
+  scrollIntoView() {
+    const elem = this.$('tr[data-category-id="' + this.get('controller.scrollIntoViewId') + '"]');
+    const scrollParent = this.$('.modal-body');
+    const eoff = elem.position();
+    const poff = $(document.getElementById('rc-scroll-anchor')).position();
+    const currHeight = scrollParent.height();
+
+    elem[0].className = "highlighted";
+
+    const goal = eoff.top - poff.top - currHeight / 2,
+      current = scrollParent.scrollTop();
+    scrollParent.scrollTop(9999999);
+    const max = scrollParent.scrollTop();
+    scrollParent.scrollTop(current);
+
+    const doneTimeout = setTimeout(function() {
+      elem[0].className = "highlighted done";
+      setTimeout(function() {
+        elem[0].className = "";
+      }, 2000);
+    }, 0);
+
+    if (goal > current - currHeight / 4 && goal < current + currHeight / 4) {
+      // Too close to goal
+      return;
+    }
+    if (max - current < 10 && goal > current) {
+      // Too close to bottom
+      return;
+    }
+    if (current < 10 && goal < current) {
+      // Too close to top
+      return;
+    }
+
+    if (!window.requestAnimationFrame) {
+      scrollParent.scrollTop(goal);
+    } else {
+      clearTimeout(doneTimeout);
+      const startTime = performance.now();
+      const duration = 100;
+
+      function doScroll(timestamp) {
+        let progress = (timestamp - startTime) / duration;
+        if (progress > 1) {
+          progress = 1;
+          setTimeout(function() {
+            elem[0].className = "highlighted done";
+            setTimeout(function() {
+              elem[0].className = "";
+            }, 2000);
+          }, 0);
+        } else if (progress < 0) {
+          progress = 0;
+        }
+        if (progress < 1) {
+          window.requestAnimationFrame(doScroll);
+        }
+
+        const iprogress = 1 - progress;
+        scrollParent.scrollTop(goal * progress + current * iprogress);
+      }
+      window.requestAnimationFrame(doScroll);
+    }
+  }
+});
diff --git a/app/assets/javascripts/main_include.js b/app/assets/javascripts/main_include.js
index 0ff24305876..5ea3455611d 100644
--- a/app/assets/javascripts/main_include.js
+++ b/app/assets/javascripts/main_include.js
@@ -94,13 +94,11 @@
 //= require ./discourse/lib/export-result
 //= require ./discourse/dialects/dialect
 //= require ./discourse/lib/emoji/emoji
-//= require ./discourse/lib/sharing
-//= require discourse/lib/desktop-notifications
+//= require_tree ./discourse/lib
 //= require ./discourse/router
 
 //= require_tree ./discourse/dialects
 //= require_tree ./discourse/controllers
-//= require_tree ./discourse/lib
 //= require_tree ./discourse/models
 //= require_tree ./discourse/components
 //= require_tree ./discourse/views
diff --git a/app/assets/stylesheets/admin.scss b/app/assets/stylesheets/admin.scss
index d1de50da4e4..577f9aba1c5 100644
--- a/app/assets/stylesheets/admin.scss
+++ b/app/assets/stylesheets/admin.scss
@@ -1 +1,2 @@
-@import "common/admin/admin_base"
+@import "common/admin/admin_base";
+@import "common/admin/cat_reorder";
diff --git a/app/assets/stylesheets/common/admin/cat_reorder.scss b/app/assets/stylesheets/common/admin/cat_reorder.scss
new file mode 100644
index 00000000000..d5619e993c3
--- /dev/null
+++ b/app/assets/stylesheets/common/admin/cat_reorder.scss
@@ -0,0 +1,28 @@
+.reorder-categories {
+  input {
+    width: 4em;
+  }
+  .th-pos {
+    width: calc(4em + 150px);
+  }
+  tbody tr {
+    background-color: transparent;
+    transition: background 0s ease;
+    &.highlighted {
+      background-color: rgba($highlight, 0.4);
+      &.done {
+        background-color: transparent;
+        transition-duration: 1s;
+      }
+    }
+    &:first-child td {
+      padding-top: 7px;
+    }
+  }
+  tbody {
+    border-bottom: 1px solid blend-primary-secondary(50%);
+  }
+  table {
+    padding-bottom: 150px;
+  }
+}
diff --git a/app/assets/stylesheets/common/base/discourse.scss b/app/assets/stylesheets/common/base/discourse.scss
index c8cedb4a6cd..d8b47398043 100644
--- a/app/assets/stylesheets/common/base/discourse.scss
+++ b/app/assets/stylesheets/common/base/discourse.scss
@@ -144,6 +144,9 @@ body {
   }
 }
 
+input[type].invalid {
+  background-color: dark-light-choose(scale-color($danger, $lightness: 80%), scale-color($danger, $lightness: -60%));
+}
 
 .wmd-input {
   resize: none;
diff --git a/app/controllers/categories_controller.rb b/app/controllers/categories_controller.rb
index 9d3ac191e9c..b63ec503dbf 100644
--- a/app/controllers/categories_controller.rb
+++ b/app/controllers/categories_controller.rb
@@ -37,7 +37,7 @@ class CategoriesController < ApplicationController
   end
 
   def move
-    guardian.ensure_can_create!(Category)
+    guardian.ensure_can_create_category!
 
     params.require("category_id")
     params.require("position")
@@ -50,6 +50,24 @@ class CategoriesController < ApplicationController
     end
   end
 
+  def reorder
+    guardian.ensure_can_create_category!
+
+    params.require(:mapping)
+    change_requests = MultiJson.load(params[:mapping])
+    by_category = Hash[change_requests.map { |cat, pos| [Category.find(cat.to_i), pos] }]
+
+    unless guardian.is_admin?
+      raise Discourse::InvalidAccess unless by_category.keys.all? { |c| guardian.can_see_category? c }
+    end
+
+    by_category.each do |cat, pos|
+      cat.position = pos
+      cat.save if cat.position_changed?
+    end
+    render json: success_json
+  end
+
   def show
     if Category.topic_create_allowed(guardian).where(id: @category.id).exists?
       @category.permission = CategoryGroup.permission_types[:full]
diff --git a/app/serializers/basic_category_serializer.rb b/app/serializers/basic_category_serializer.rb
index 96b0268cfae..f62968a59f2 100644
--- a/app/serializers/basic_category_serializer.rb
+++ b/app/serializers/basic_category_serializer.rb
@@ -7,6 +7,7 @@ class BasicCategorySerializer < ApplicationSerializer
              :slug,
              :topic_count,
              :post_count,
+             :position,
              :description,
              :description_text,
              :topic_url,
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index e92de892cfe..06f06b09f58 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -367,6 +367,10 @@ en:
       all_subcategories: "all"
       no_subcategory: "none"
       category: "Category"
+      reorder:
+        title: "Reorder Categories"
+        save: "Save Order"
+        apply_all: "Apply"
       posts: "Posts"
       topics: "Topics"
       latest: "Latest"
@@ -1546,6 +1550,7 @@ en:
       add_permission: "Add Permission"
       this_year: "this year"
       position: "position"
+      reorder: "Reorder"
       default_position: "Default Position"
       position_disabled: "Categories will be displayed in order of activity. To control the order of categories in lists, "
       position_disabled_click: 'enable the "fixed category positions" setting.'
diff --git a/config/routes.rb b/config/routes.rb
index f10ea5c2e95..d2adc0cfdb4 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -382,6 +382,7 @@ Discourse::Application.routes.draw do
 
   resources :categories, :except => :show
   post "category/:category_id/move" => "categories#move"
+  post "categories/reorder" => "categories#reorder"
   post "category/:category_id/notifications" => "categories#set_notifications"
   put "category/:category_id/slug" => "categories#update_slug"
 
diff --git a/spec/controllers/categories_controller_spec.rb b/spec/controllers/categories_controller_spec.rb
index e838b2e9714..f03cfd05e8c 100644
--- a/spec/controllers/categories_controller_spec.rb
+++ b/spec/controllers/categories_controller_spec.rb
@@ -95,6 +95,42 @@ describe CategoriesController do
 
   end
 
+  describe "reorder" do
+    it "reorders the categories" do
+      admin = log_in(:admin)
+
+      c1 = Fabricate(:category)
+      c2 = Fabricate(:category)
+      c3 = Fabricate(:category)
+      c4 = Fabricate(:category)
+      if c3.id < c2.id
+        tmp = c3; c2 = c3; c3 = tmp;
+      end
+      c1.position = 8
+      c2.position = 6
+      c3.position = 7
+      c4.position = 5
+
+      payload = {}
+      payload[c1.id] = 4
+      payload[c2.id] = 6
+      payload[c3.id] = 6
+      payload[c4.id] = 5
+
+      xhr :post, :reorder, mapping: MultiJson.dump(payload)
+
+      SiteSetting.fixed_category_positions = true
+      list = CategoryList.new(Guardian.new(admin))
+      expect(list.categories).to eq([
+                                      Category.find(SiteSetting.uncategorized_category_id),
+                                      c1,
+                                      c4,
+                                      c2,
+                                      c3
+                                    ])
+    end
+  end
+
   describe "update" do
 
     it "requires the user to be logged in" do