diff --git a/app/assets/javascripts/layout_nav.js b/app/assets/javascripts/layout_nav.js
index 71064ccc539..e8f59f30035 100644
--- a/app/assets/javascripts/layout_nav.js
+++ b/app/assets/javascripts/layout_nav.js
@@ -1,5 +1,6 @@
 /* eslint-disable func-names, space-before-function-paren, no-var, prefer-arrow-callback, no-unused-vars, one-var, one-var-declaration-per-line, vars-on-top, max-len */
 import _ from 'underscore';
+import NewNavSidebar from './new_sidebar';
 
 (function() {
   var hideEndFade;
@@ -53,6 +54,7 @@ import _ from 'underscore';
   }
 
   $(() => {
+    new NewNavSidebar();
     $(window).on('scroll', _.throttle(applyScrollNavClass, 100));
   });
 }).call(window);
diff --git a/app/assets/javascripts/new_sidebar.js b/app/assets/javascripts/new_sidebar.js
new file mode 100644
index 00000000000..4aadeb6b462
--- /dev/null
+++ b/app/assets/javascripts/new_sidebar.js
@@ -0,0 +1,23 @@
+const SIDEBAR_EXPANDED_CLASS = 'nav-sidebar-expanded';
+
+export default class NewNavSidebar {
+  constructor() {
+    this.initDomElements();
+    this.bindEvents();
+  }
+
+  initDomElements() {
+    this.$sidebar = $('.nav-sidebar');
+    this.$openSidebar = $('.toggle-mobile-nav');
+    this.$closeSidebar = $('.close-nav-button');
+  }
+
+  bindEvents() {
+    this.$openSidebar.on('click', e => this.toggleSidebarNav(e, true));
+    this.$closeSidebar.on('click', e => this.toggleSidebarNav(e, false));
+  }
+
+  toggleSidebarNav(show) {
+    this.$sidebar.toggleClass(SIDEBAR_EXPANDED_CLASS, show);
+  }
+}
diff --git a/app/assets/stylesheets/new_nav.scss b/app/assets/stylesheets/new_nav.scss
index 393d5006e24..03ba0afe940 100644
--- a/app/assets/stylesheets/new_nav.scss
+++ b/app/assets/stylesheets/new_nav.scss
@@ -275,8 +275,6 @@ header.navbar-gitlab-new {
 .breadcrumbs {
   display: flex;
   min-height: 60px;
-  padding-top: $gl-padding-top;
-  padding-bottom: $gl-padding-top;
   color: $gl-text-color;
   border-bottom: 1px solid $border-color;
 
@@ -300,6 +298,7 @@ header.navbar-gitlab-new {
   display: flex;
   width: 100%;
   position: relative;
+  align-items: center;
 
   .dropdown-menu-projects {
     margin-top: -$gl-padding;
diff --git a/app/assets/stylesheets/new_sidebar.scss b/app/assets/stylesheets/new_sidebar.scss
index 82cabefa129..eaf7daaa5cf 100644
--- a/app/assets/stylesheets/new_sidebar.scss
+++ b/app/assets/stylesheets/new_sidebar.scss
@@ -26,41 +26,75 @@ $new-sidebar-width: 220px;
 }
 
 .context-header {
-  border-bottom: 1px solid $border-color;
-  font-weight: 600;
-  display: flex;
-  align-items: center;
-  padding: 10px 16px 10px 10px;
-  color: $gl-text-color;
+  position: relative;
+
+  a {
+    border-bottom: 1px solid $border-color;
+    font-weight: 600;
+    display: flex;
+    align-items: center;
+    padding: 10px 16px 10px 10px;
+    color: $gl-text-color;
+
+    @media (max-width: $screen-xs-max) {
+      padding-right: 30px;
+    }
+
+    &:hover {
+      background-color: $hover-background;
+      color: $hover-color;
+      border-color: $hover-background;
+
+      .avatar-container {
+        border-color: transparent;
+      }
+
+      .settings-avatar {
+        background-color: $indigo-500;
+
+        i {
+          color: $hover-color;
+        }
+      }
+    }
+  }
 
   .avatar-container {
     flex: 0 0 40px;
     background-color: $white-light;
   }
 
-  &:hover {
-    background-color: $hover-background;
-    color: $hover-color;
-    border-color: $hover-background;
-
-    .avatar-container {
-      border-color: transparent;
-    }
-
-    .settings-avatar {
-      background-color: $indigo-500;
-
-      i {
-        color: $hover-color;
-      }
-    }
-  }
-
   .project-title,
   .group-title {
     overflow: hidden;
     text-overflow: ellipsis;
   }
+
+
+  &:hover {
+    .close-nav-button {
+      color: $white-light;
+    }
+  }
+
+  .close-nav-button {
+    display: none;
+    position: absolute;
+    top: 0;
+    right: 0;
+    height: 100%;
+    background-color: transparent;
+    border: 0;
+    padding: 0 10px;
+
+    @media (max-width: $screen-xs-max) {
+      display: block;
+    }
+
+    &:hover {
+      color: $gl-text-color;
+    }
+  }
 }
 
 .settings-avatar {
@@ -89,6 +123,10 @@ $new-sidebar-width: 220px;
   background-color: $gray-normal;
   box-shadow: inset -2px 0 0 $border-color;
 
+  &.nav-sidebar-expanded {
+    width: $new-sidebar-width;
+  }
+
   a {
     text-decoration: none;
   }
@@ -185,6 +223,25 @@ $new-sidebar-width: 220px;
   }
 }
 
+.toggle-mobile-nav {
+  display: none;
+  background-color: transparent;
+  border: 0;
+  padding: 6px 16px;
+  margin: 0 16px 0 -15px;
+  height: 46px;
+  border-right: 1px solid $gl-text-color-quaternary;
+
+  i {
+    font-size: 20px;
+    color: $gl-text-color-secondary;
+  }
+
+  @media (max-width: $screen-xs-max) {
+    display: inline-block;
+  }
+}
+
 
 // Make issue boards full-height now that sub-nav is gone
 
diff --git a/app/views/layouts/nav/_breadcrumbs.html.haml b/app/views/layouts/nav/_breadcrumbs.html.haml
index b0c1ab7420f..475d89f1156 100644
--- a/app/views/layouts/nav/_breadcrumbs.html.haml
+++ b/app/views/layouts/nav/_breadcrumbs.html.haml
@@ -3,6 +3,8 @@
 
 %nav.breadcrumbs{ role: "navigation" }
   .breadcrumbs-container{ class: [container_class, @content_class] }
+    %button.toggle-mobile-nav
+      = icon ('bars')
     .breadcrumbs-links.js-title-container
       - unless hide_top_links
         .title
diff --git a/app/views/layouts/nav/_new_project_sidebar.html.haml b/app/views/layouts/nav/_new_project_sidebar.html.haml
index 7c9822c5a6a..baf257d06e0 100644
--- a/app/views/layouts/nav/_new_project_sidebar.html.haml
+++ b/app/views/layouts/nav/_new_project_sidebar.html.haml
@@ -1,10 +1,13 @@
 .nav-sidebar
   - can_edit = can?(current_user, :admin_project, @project)
-  = link_to project_path(@project), title: @project.name, class: 'context-header' do
-    .avatar-container.s40.project-avatar
-      = project_icon(@project, alt: @project.name, class: 'avatar s40 avatar-tile')
-    .project-title
-      = @project.name
+  .context-header
+    = link_to project_path(@project), title: @project.name do
+      .avatar-container.s40.project-avatar
+        = project_icon(@project, alt: @project.name, class: 'avatar s40 avatar-tile')
+      .project-title
+        = @project.name
+    %button.close-nav-button
+      = icon('times')
   %ul.sidebar-top-level-items
     = nav_link(path: ['projects#show', 'projects#activity', 'cycle_analytics#show'], html_options: { class: 'home' }) do
       = link_to project_path(@project), title: 'Project', class: 'shortcuts-project' do