diff --git a/docs/components/navs.md b/docs/components/navs.md
index 7ac1b52324..2db4f4703b 100644
--- a/docs/components/navs.md
+++ b/docs/components/navs.md
@@ -321,7 +321,7 @@ Use the tab JavaScript plugin—include it individually or through the compiled
     </li>
   </ul>
   <div class="tab-content" id="myTabContent">
-    <div role="tabpanel" class="tab-pane fade in active" id="home" aria-labelledBy="home-tab">
+    <div role="tabpanel" class="tab-pane fade show active" id="home" aria-labelledBy="home-tab">
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     </div>
     <div class="tab-pane fade" id="profile" role="tabpanel" aria-labelledBy="profile-tab">
@@ -390,11 +390,11 @@ $('#myTab li:eq(2) a').tab('show') // Select third tab (0-indexed)
 
 ### Fade effect
 
-To make tabs fade in, add `.fade` to each `.tab-pane`. The first tab pane must also have `.in` to make the initial content visible.
+To make tabs fade in, add `.fade` to each `.tab-pane`. The first tab pane must also have `.show` to make the initial content visible.
 
 {% highlight html %}
 <div class="tab-content">
-  <div class="tab-pane fade in active" id="home" role="tabpanel">...</div>
+  <div class="tab-pane fade show active" id="home" role="tabpanel">...</div>
   <div class="tab-pane fade" id="profile" role="tabpanel">...</div>
   <div class="tab-pane fade" id="messages" role="tabpanel">...</div>
   <div class="tab-pane fade" id="settings" role="tabpanel">...</div>
diff --git a/js/src/tab.js b/js/src/tab.js
index e7e8f550f0..c7e5fbfbe9 100644
--- a/js/src/tab.js
+++ b/js/src/tab.js
@@ -37,7 +37,7 @@ const Tab = (($) => {
     DROPDOWN_MENU : 'dropdown-menu',
     ACTIVE        : 'active',
     FADE          : 'fade',
-    IN            : 'in'
+    SHOW          : 'show'
   }
 
   const Selector = {
@@ -173,7 +173,7 @@ const Tab = (($) => {
       }
 
       if (active) {
-        $(active).removeClass(ClassName.IN)
+        $(active).removeClass(ClassName.SHOW)
       }
     }
 
@@ -197,7 +197,7 @@ const Tab = (($) => {
 
       if (isTransitioning) {
         Util.reflow(element)
-        $(element).addClass(ClassName.IN)
+        $(element).addClass(ClassName.SHOW)
       } else {
         $(element).removeClass(ClassName.FADE)
       }