diff --git a/lib/rdoc/generator/template/aliki/class.rhtml b/lib/rdoc/generator/template/aliki/class.rhtml
index 2e812478e0..69adfab1ad 100644
--- a/lib/rdoc/generator/template/aliki/class.rhtml
+++ b/lib/rdoc/generator/template/aliki/class.rhtml
@@ -3,7 +3,7 @@
 <%= render '_header.rhtml' %>
 <%= render '_sidebar_toggle.rhtml' %>
 
-<nav id="navigation" role="navigation">
+<nav id="navigation" role="navigation" hidden>
   <%= render '_sidebar_pages.rhtml' %>
   <%= render '_sidebar_sections.rhtml' %>
   <%= render '_sidebar_ancestors.rhtml' %>
diff --git a/lib/rdoc/generator/template/aliki/index.rhtml b/lib/rdoc/generator/template/aliki/index.rhtml
index 12ac5a2962..23103345b1 100644
--- a/lib/rdoc/generator/template/aliki/index.rhtml
+++ b/lib/rdoc/generator/template/aliki/index.rhtml
@@ -3,7 +3,7 @@
 <%= render '_header.rhtml' %>
 <%= render '_sidebar_toggle.rhtml' %>
 
-<nav id="navigation" role="navigation">
+<nav id="navigation" role="navigation" hidden>
   <%= render '_sidebar_pages.rhtml' %>
   <%= render '_sidebar_classes.rhtml' %>
 </nav>
diff --git a/lib/rdoc/generator/template/aliki/js/aliki.js b/lib/rdoc/generator/template/aliki/js/aliki.js
index 6b38c46266..887a0cf204 100644
--- a/lib/rdoc/generator/template/aliki/js/aliki.js
+++ b/lib/rdoc/generator/template/aliki/js/aliki.js
@@ -158,9 +158,12 @@ function hookSidebar() {
   });
 
   const isSmallViewport = window.matchMedia("(max-width: 1023px)").matches;
-  if (isSmallViewport) {
-    closeNav();
 
+  // The sidebar is hidden by default with the `hidden` attribute
+  // On large viewports, we display the sidebar with JavaScript
+  // This is better than the opposite approach of hiding it with JavaScript
+  // because it avoids flickering the sidebar when the page is loaded, especially on mobile devices
+  if (isSmallViewport) {
     // Close nav when clicking links inside it
     document.addEventListener('click', (e) => {
       if (e.target.closest('#navigation a')) {
@@ -176,6 +179,8 @@ function hookSidebar() {
         closeNav();
       }
     });
+  } else {
+    openNav();
   }
 }
 
diff --git a/lib/rdoc/generator/template/aliki/page.rhtml b/lib/rdoc/generator/template/aliki/page.rhtml
index 3e19f1c3e6..e7b0dc66cc 100644
--- a/lib/rdoc/generator/template/aliki/page.rhtml
+++ b/lib/rdoc/generator/template/aliki/page.rhtml
@@ -3,7 +3,7 @@
 <%= render '_header.rhtml' %>
 <%= render '_sidebar_toggle.rhtml' %>
 
-<nav id="navigation" role="navigation">
+<nav id="navigation" role="navigation" hidden>
   <%= render '_sidebar_pages.rhtml' %>
   <%= render '_sidebar_classes.rhtml' %>
 </nav>
diff --git a/lib/rdoc/generator/template/aliki/servlet_not_found.rhtml b/lib/rdoc/generator/template/aliki/servlet_not_found.rhtml
index 8f0845382e..6ad306c625 100644
--- a/lib/rdoc/generator/template/aliki/servlet_not_found.rhtml
+++ b/lib/rdoc/generator/template/aliki/servlet_not_found.rhtml
@@ -1,7 +1,7 @@
 <body role="document">
 <%= render '_sidebar_toggle.rhtml' %>
 
-<nav id="navigation" role="navigation">
+<nav id="navigation" role="navigation" hidden>
   <%= render '_sidebar_pages.rhtml' %>
   <%= render '_sidebar_classes.rhtml' %>
 </nav>
diff --git a/lib/rdoc/generator/template/aliki/servlet_root.rhtml b/lib/rdoc/generator/template/aliki/servlet_root.rhtml
index 35b4815215..1f9c2eb20e 100644
--- a/lib/rdoc/generator/template/aliki/servlet_root.rhtml
+++ b/lib/rdoc/generator/template/aliki/servlet_root.rhtml
@@ -1,7 +1,7 @@
 <body role="document">
 <%= render '_sidebar_toggle.rhtml' %>
 
-<nav id="navigation" role="navigation">
+<nav id="navigation" role="navigation" hidden>
   <div id="project-navigation">
     <div id="home-section" class="nav-section">
       <h2>
diff --git a/test/rdoc/generator/aliki_test.rb b/test/rdoc/generator/aliki_test.rb
index 387e541a07..cebd0c9b96 100644
--- a/test/rdoc/generator/aliki_test.rb
+++ b/test/rdoc/generator/aliki_test.rb
@@ -228,7 +228,7 @@ def test_generate
     index = File.binread('index.html')
     assert_match %r{<html lang="en">}, index
     assert_match %r{<body role="document"}, index
-    assert_match %r{<nav id="navigation" role="navigation">}, index
+    assert_match %r{<nav id="navigation" role="navigation" hidden>}, index
     assert_match %r{<main role="main">}, index
   end
 
