diff --git a/docs/examples/carousel/index.html b/docs/examples/carousel/index.html
index 3397a3a7e3..5503b0eab8 100644
--- a/docs/examples/carousel/index.html
+++ b/docs/examples/carousel/index.html
@@ -129,7 +129,7 @@
           <p class="lead">Donec ullamcorper nulla non metus auctor fringilla. Vestibulum id ligula porta felis euismod semper. Praesent commodo cursus magna, vel scelerisque nisl consectetur. Fusce dapibus, tellus ac cursus commodo.</p>
         </div>
         <div class="col-md-5">
-          <img class="featurette-image img-fluid m-x-auto" data-src="holder.js/500x500/auto" alt="Generic placeholder image">
+          <img class="featurette-image img-fluid mx-auto" data-src="holder.js/500x500/auto" alt="Generic placeholder image">
         </div>
       </div>
 
@@ -141,7 +141,7 @@
           <p class="lead">Donec ullamcorper nulla non metus auctor fringilla. Vestibulum id ligula porta felis euismod semper. Praesent commodo cursus magna, vel scelerisque nisl consectetur. Fusce dapibus, tellus ac cursus commodo.</p>
         </div>
         <div class="col-md-5 pull-md-7">
-          <img class="featurette-image img-fluid m-x-auto" data-src="holder.js/500x500/auto" alt="Generic placeholder image">
+          <img class="featurette-image img-fluid mx-auto" data-src="holder.js/500x500/auto" alt="Generic placeholder image">
         </div>
       </div>
 
@@ -153,7 +153,7 @@
           <p class="lead">Donec ullamcorper nulla non metus auctor fringilla. Vestibulum id ligula porta felis euismod semper. Praesent commodo cursus magna, vel scelerisque nisl consectetur. Fusce dapibus, tellus ac cursus commodo.</p>
         </div>
         <div class="col-md-5">
-          <img class="featurette-image img-fluid m-x-auto" data-src="holder.js/500x500/auto" alt="Generic placeholder image">
+          <img class="featurette-image img-fluid mx-auto" data-src="holder.js/500x500/auto" alt="Generic placeholder image">
         </div>
       </div>
 
diff --git a/docs/examples/navbar-top-fixed/index.html b/docs/examples/navbar-top-fixed/index.html
index 45514d854e..1ecbd2c3b4 100644
--- a/docs/examples/navbar-top-fixed/index.html
+++ b/docs/examples/navbar-top-fixed/index.html
@@ -21,7 +21,7 @@
 
     <div class="pos-f-t">
       <div class="collapse" id="navbar-header">
-        <div class="container-fluid bg-inverse p-a-1">
+        <div class="container-fluid bg-inverse p-1">
           <h3>Collapsed content</h3>
           <p>Toggleable via the navbar brand.</p>
         </div>
diff --git a/docs/examples/navbar-top/index.html b/docs/examples/navbar-top/index.html
index 66e7754adb..d86704e357 100644
--- a/docs/examples/navbar-top/index.html
+++ b/docs/examples/navbar-top/index.html
@@ -20,12 +20,12 @@
   <body>
 
     <div class="collapse" id="navbar-header">
-      <div class="container-fluid bg-inverse p-a-1">
+      <div class="container-fluid bg-inverse p-1">
         <h3>Collapsed content</h3>
         <p>Toggleable via the navbar brand.</p>
       </div>
     </div>
-    <div class="navbar navbar-light bg-faded navbar-static-top m-b-1">
+    <div class="navbar navbar-light bg-faded navbar-static-top mb-1">
       <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbar-header" aria-controls="navbar-header" aria-expanded="false" aria-label="Toggle navigation"></button>
     </div>
 
diff --git a/docs/examples/sticky-footer-navbar/index.html b/docs/examples/sticky-footer-navbar/index.html
index efe9b4c64d..855f0418d6 100644
--- a/docs/examples/sticky-footer-navbar/index.html
+++ b/docs/examples/sticky-footer-navbar/index.html
@@ -23,7 +23,7 @@
     <!-- Fixed navbar -->
     <div class="pos-f-t">
       <div class="collapse" id="navbar-header">
-        <div class="container bg-inverse p-a-1">
+        <div class="container bg-inverse p-1">
           <h3>Collapsed content</h3>
           <p>Toggleable via the navbar brand.</p>
         </div>
@@ -54,7 +54,7 @@
 
     <!-- Begin page content -->
     <div class="container">
-      <div class="m-t-1">
+      <div class="mt-1">
         <h1>Sticky footer with fixed navbar</h1>
       </div>
       <p class="lead">Pin a fixed-height footer to the bottom of the viewport in desktop browsers with this custom HTML and CSS. A fixed navbar has been added with <code>padding-top: 60px;</code> on the <code>body &gt; .container</code>.</p>
diff --git a/docs/examples/sticky-footer/index.html b/docs/examples/sticky-footer/index.html
index bc16be2519..3d305166e9 100644
--- a/docs/examples/sticky-footer/index.html
+++ b/docs/examples/sticky-footer/index.html
@@ -22,7 +22,7 @@
 
     <!-- Begin page content -->
     <div class="container">
-      <div class="m-t-1">
+      <div class="mt-1">
         <h1>Sticky footer</h1>
       </div>
       <p class="lead">Pin a fixed-height footer to the bottom of the viewport in desktop browsers with this custom HTML and CSS.</p>
diff --git a/docs/index.html b/docs/index.html
index 6ecac79796..3fe4c513bf 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -20,14 +20,14 @@ layout: home
     <p class="lead">Quickly include Bootstrap's CSS and JS into any project. Use your favorite package manager, download the source, or use the Bootstrap CDN.</p>
 
     <div class="row">
-      <div class="col-sm-6 m-b-3">
+      <div class="col-sm-6 mb-3">
         <h4>Managed dependencies</h4>
         <p>Include Bootstrap's source Sass and JavaScript files via Bower, Composer, Meteor, or npm. Package managed installs don't include documentation, but do include our Gruntfile and readme.</p>
         <p>
           <a class="btn btn-bs btn-outline" href="{{ site.baseurl }}/getting-started/download/#package-managers">View install methods</a>
         </p>
       </div>
-      <div class="col-sm-6 m-b-3">
+      <div class="col-sm-6 mb-3">
         <h4>Bootstrap CDN</h4>
         <p>When you just need to include Bootstrap's compiled CSS and JS, use the Bootstrap CDN, free from the Max CDN folks.</p>
 {% highlight html %}
@@ -37,7 +37,7 @@ layout: home
       </div>
     </div>
 
-    <hr class="half-rule m-t-0">
+    <hr class="half-rule mt-0">
 
     <p><strong>Looking for something else?</strong> Compiled builds of Bootstrap's CSS and JS are also available.</p>
     <a href="{{ site.baseurl }}/getting-started/download/" class="btn btn-bs btn-outline">More download options</a>
@@ -50,24 +50,24 @@ layout: home
     <p class="lead">Bootstrap makes front-end web development faster and easier. It's made for folks of all skill levels, devices of all shapes, and projects of all sizes.</p>
 
     <div class="row">
-      <div class="col-sm-4 m-b-3">
+      <div class="col-sm-4 mb-3">
         <img src="{{ site.baseurl }}/assets/img/sass.png" alt="Sass support" class="img-fluid">
         <h4>Preprocessor</h4>
         <p>Bootstrap ships with vanilla CSS, but its source code utilizes <a href="http://sass-lang.com/">Sass</a>, a popular CSS preprocessor. Quickly get started with precompiled CSS or build on the source.</p>
       </div>
-      <div class="col-sm-4 m-b-3">
+      <div class="col-sm-4 mb-3">
         <img src="{{ site.baseurl }}/assets/img/devices.png" alt="Responsive across devices" class="img-fluid">
         <h4>One framework, every device.</h4>
         <p>Bootstrap easily and efficiently scales your websites and applications with a single code base, from phones to tablets to desktops with CSS media queries.</p>
       </div>
-      <div class="col-sm-4 m-b-3">
+      <div class="col-sm-4 mb-3">
         <img src="{{ site.baseurl }}/assets/img/components.png" alt="Components" class="img-fluid">
         <h4>Full of features</h4>
         <p>With Bootstrap, you get extensive and beautiful documentation for common HTML elements, dozens of custom HTML and CSS components, and awesome jQuery plugins.</p>
       </div>
     </div>
 
-    <hr class="half-rule m-t-0">
+    <hr class="half-rule mt-0">
 
     <p><strong>Bootstrap is open source!</strong> It's hosted, developed, and maintained on GitHub by folks like you.</p>
     <a href="{{ site.repo }}" class="btn btn-bs btn-outline">View the GitHub project</a>
@@ -85,7 +85,7 @@ layout: home
       <a href="{{ site.themes }}" class="btn btn-bs btn-outline">Browse themes</a>
     </p>
 
-    <img class="img-fluid m-x-auto" src="{{ site.baseurl }}/assets/img/bs-themes.png" alt="Bootstrap Themes" width="1024" height="388">
+    <img class="img-fluid mx-auto" src="{{ site.baseurl }}/assets/img/bs-themes.png" alt="Bootstrap Themes" width="1024" height="388">
   </div>
 </div>
 
diff --git a/js/tests/visual/collapse.html b/js/tests/visual/collapse.html
index 3208069cbe..ec7a6f29a6 100644
--- a/js/tests/visual/collapse.html
+++ b/js/tests/visual/collapse.html
@@ -16,7 +16,7 @@
   <div id="accordion">
     <div class="card">
       <div class="card-header">
-        <h5 class="m-b-0">
+        <h5 class="mb-0">
           <a role="button" data-toggle="collapse" data-parent="#accordion" href="#collapseOne">
             Collapsible Group Item #1
           </a>
@@ -30,7 +30,7 @@
     </div>
     <div class="card">
       <div class="card-header">
-        <h5 class="m-b-0">
+        <h5 class="mb-0">
           <a role="button" data-toggle="collapse" data-parent="#accordion" href="#collapseTwo">
             Collapsible Group Item #2
           </a>
@@ -44,7 +44,7 @@
     </div>
     <div class="card">
       <div class="card-header">
-        <h5 class="m-b-0">
+        <h5 class="mb-0">
           <a role="button" data-toggle="collapse" data-parent="#accordion" href="#collapseThree">
             Collapsible Group Item #3
           </a>
diff --git a/js/tests/visual/dropdown.html b/js/tests/visual/dropdown.html
index 10cf6dad90..7dce87bd1b 100644
--- a/js/tests/visual/dropdown.html
+++ b/js/tests/visual/dropdown.html
@@ -20,7 +20,7 @@
 
     <div class="collapse navbar-toggleable-xs" id="exCollapsingNavbar2">
 
-      <ul class="nav navbar-nav pull-left">
+      <ul class="nav navbar-nav float-xs-left">
 
         <li class="dropdown nav-item">
           <a id="drop1" href="#" role="button" class="dropdown-toggle nav-link" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
@@ -50,7 +50,7 @@
 
       </ul>
 
-      <ul class="nav navbar-nav pull-right">
+      <ul class="nav navbar-nav float-xs-right">
         <li id="fat-menu" class="dropdown nav-item">
           <a href="#" id="drop3" role="button" class="dropdown-toggle nav-link" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
             Dropdown 3
@@ -67,7 +67,7 @@
     </div>
   </nav>
 
-  <ul class="nav nav-pills m-t-lg">
+  <ul class="nav nav-pills mt-3">
     <li class="active nav-item"><a href="#" class="nav-link">Regular link</a></li>
     <li class="dropdown nav-item">
       <a id="drop4" class="nav-link" role="button" data-toggle="dropdown" href="#" aria-haspopup="true" aria-expanded="false">
diff --git a/js/tests/visual/modal.html b/js/tests/visual/modal.html
index 86c4a10ec7..a9e2c2440a 100644
--- a/js/tests/visual/modal.html
+++ b/js/tests/visual/modal.html
@@ -40,7 +40,7 @@
   </div>
 </nav>
 
-<div class="container m-t-lg">
+<div class="container mt-3">
 
   <h1>Modal <small>Bootstrap Visual Test</small></h1>
 
@@ -65,7 +65,7 @@
           <div id="accordion" role="tablist" aria-multiselectable="true">
             <div class="card">
               <div class="card-header" role="tab" id="headingOne">
-                <h5 class="m-b-0">
+                <h5 class="mb-0">
                   <a role="button" data-toggle="collapse" data-parent="#accordion" href="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
                     Collapsible Group Item #1
                   </a>
@@ -79,7 +79,7 @@
             </div>
             <div class="card">
               <div class="card-header" role="tab" id="headingTwo">
-                <h5 class="m-b-0">
+                <h5 class="mb-0">
                   <a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion" href="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo">
                     Collapsible Group Item #2
                   </a>
