diff --git a/packages/docusaurus-theme-classic/package.json b/packages/docusaurus-theme-classic/package.json
index b0772cf832..809cf1280e 100644
--- a/packages/docusaurus-theme-classic/package.json
+++ b/packages/docusaurus-theme-classic/package.json
@@ -9,7 +9,8 @@
   "license": "MIT",
   "dependencies": {
     "classnames": "^2.2.6",
-    "docsearch.js": "^2.5.2"
+    "docsearch.js": "^2.5.2",
+    "react-toggle": "^4.0.2"
   },
   "peerDependencies": {
     "@docusaurus/core": "^2.0.0",
diff --git a/packages/docusaurus-theme-classic/src/theme/Navbar/index.js b/packages/docusaurus-theme-classic/src/theme/Navbar/index.js
index dc4724dd7a..850c8f2c4a 100644
--- a/packages/docusaurus-theme-classic/src/theme/Navbar/index.js
+++ b/packages/docusaurus-theme-classic/src/theme/Navbar/index.js
@@ -5,9 +5,11 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import React, {useCallback, useState} from 'react';
+import React, {useCallback, useState, useEffect} from 'react';
+import Toggle from 'react-toggle';
 
 import Link from '@docusaurus/Link';
+import Head from '@docusaurus/Head';
 import useDocusaurusContext from '@docusaurus/useDocusaurusContext';
 import withBaseUrl from '@docusaurus/withBaseUrl';
 
@@ -15,6 +17,8 @@ import SearchBar from '@theme/SearchBar';
 
 import classnames from 'classnames';
 
+import './styles.css';
+
 function NavLink(props) {
   return (
     <Link
@@ -38,6 +42,11 @@ function NavLink(props) {
 function Navbar() {
   const context = useDocusaurusContext();
   const [sidebarShown, setSidebarShown] = useState(false);
+  const currentTheme =
+    typeof document !== 'undefined'
+      ? document.querySelector('html').getAttribute('data-theme')
+      : '';
+  const [theme, setTheme] = useState(currentTheme);
   const {siteConfig = {}} = context;
   const {baseUrl, themeConfig = {}} = siteConfig;
   const {algolia, navbar = {}} = themeConfig;
@@ -50,107 +59,145 @@ function Navbar() {
     setSidebarShown(false);
   }, [setSidebarShown]);
 
+  useEffect(() => {
+    try {
+      const localStorageTheme = localStorage.getItem('theme');
+      setTheme(localStorageTheme);
+    } catch (err) {
+      console.error(err);
+    }
+  }, []);
+
+  const onToggleChange = e => {
+    const nextTheme = e.target.checked ? 'dark' : '';
+    setTheme(nextTheme);
+    try {
+      localStorage.setItem('theme', nextTheme);
+    } catch (err) {
+      console.error(err);
+    }
+  };
+
   return (
-    <nav
-      className={classnames('navbar', 'navbar--light', 'navbar--fixed-top', {
-        'navbar--sidebar-show': sidebarShown,
-      })}>
-      <div className="navbar__inner">
-        <div className="navbar__items">
-          <div
-            aria-label="Navigation bar toggle"
-            className="navbar__toggle"
-            role="button"
-            tabIndex={0}
-            onClick={showSidebar}
-            onKeyDown={showSidebar}>
-            <svg
-              xmlns="http://www.w3.org/2000/svg"
-              width="30"
-              height="30"
-              viewBox="0 0 30 30"
-              role="img"
-              focusable="false">
-              <title>Menu</title>
-              <path
-                stroke="currentColor"
-                strokeLinecap="round"
-                strokeMiterlimit="10"
-                strokeWidth="2"
-                d="M4 7h22M4 15h22M4 23h22"
-              />
-            </svg>
-          </div>
-          <Link className="navbar__brand" to={baseUrl}>
-            {logo != null && (
-              <img
-                className="navbar__logo"
-                src={withBaseUrl(logo.src)}
-                alt={logo.alt}
-              />
-            )}
-            {title != null && <strong>{title}</strong>}
-          </Link>
-          {links
-            .filter(linkItem => linkItem.position !== 'right')
-            .map((linkItem, i) => (
-              <NavLink {...linkItem} key={i} />
-            ))}
-        </div>
-        <div className="navbar__items navbar__items--right">
-          {links
-            .filter(linkItem => linkItem.position === 'right')
-            .map((linkItem, i) => (
-              <NavLink {...linkItem} key={i} />
-            ))}
-          {algolia && (
-            <div className="navbar__search" key="search-box">
-              <SearchBar />
+    <React.Fragment>
+      <Head>
+        {/* TODO: Do not assume that it is in english language */}
+        <html lang="en" data-theme={theme} />
+      </Head>
+      <nav
+        className={classnames('navbar', 'navbar--light', 'navbar--fixed-top', {
+          'navbar--sidebar-show': sidebarShown,
+        })}>
+        <div className="navbar__inner">
+          <div className="navbar__items">
+            <div
+              aria-label="Navigation bar toggle"
+              className="navbar__toggle"
+              role="button"
+              tabIndex={0}
+              onClick={showSidebar}
+              onKeyDown={showSidebar}>
+              <svg
+                xmlns="http://www.w3.org/2000/svg"
+                width="30"
+                height="30"
+                viewBox="0 0 30 30"
+                role="img"
+                focusable="false">
+                <title>Menu</title>
+                <path
+                  stroke="currentColor"
+                  strokeLinecap="round"
+                  strokeMiterlimit="10"
+                  strokeWidth="2"
+                  d="M4 7h22M4 15h22M4 23h22"
+                />
+              </svg>
             </div>
-          )}
-        </div>
-      </div>
-      <div
-        role="presentation"
-        className="navbar__sidebar__backdrop"
-        onClick={() => {
-          setSidebarShown(false);
-        }}
-      />
-      <div className="navbar__sidebar">
-        <div className="navbar__sidebar__brand">
-          <a
-            className="navbar__brand"
-            href="#!"
-            role="button"
-            onClick={hideSidebar}>
-            {logo != null && (
-              <img
-                className="navbar__logo"
-                src={withBaseUrl(logo.src)}
-                alt={logo.alt}
-              />
-            )}
-            {title != null && <strong>{title}</strong>}
-          </a>
-        </div>
-        <div className="navbar__sidebar__items">
-          <div className="menu">
-            <ul className="menu__list">
-              {links.map((linkItem, i) => (
-                <li className="menu__list-item" key={i}>
-                  <NavLink
-                    className="menu__link"
-                    {...linkItem}
-                    onClick={hideSidebar}
-                  />
-                </li>
+            <Link className="navbar__brand" to={baseUrl}>
+              {logo != null && (
+                <img
+                  className="navbar__logo"
+                  src={withBaseUrl(logo.src)}
+                  alt={logo.alt}
+                />
+              )}
+              {title != null && <strong>{title}</strong>}
+            </Link>
+            {links
+              .filter(linkItem => linkItem.position !== 'right')
+              .map((linkItem, i) => (
+                <NavLink {...linkItem} key={i} />
               ))}
-            </ul>
+          </div>
+          <div className="navbar__items navbar__items--right">
+            {links
+              .filter(linkItem => linkItem.position === 'right')
+              .map((linkItem, i) => (
+                <NavLink {...linkItem} key={i} />
+              ))}
+            <Toggle
+              className="large__viewport"
+              aria-label="Dark mode toggle"
+              checked={theme === 'dark'}
+              onChange={onToggleChange}
+            />
+            {algolia && (
+              <div className="navbar__search" key="search-box">
+                <SearchBar />
+              </div>
+            )}
           </div>
         </div>
-      </div>
-    </nav>
+        <div
+          role="presentation"
+          className="navbar__sidebar__backdrop"
+          onClick={() => {
+            setSidebarShown(false);
+          }}
+        />
+        <div className="navbar__sidebar">
+          <div className="navbar__sidebar__brand">
+            <a
+              className="navbar__brand"
+              href="#!"
+              role="button"
+              onClick={hideSidebar}>
+              {logo != null && (
+                <img
+                  className="navbar__logo"
+                  src={withBaseUrl(logo.src)}
+                  alt={logo.alt}
+                />
+              )}
+              {title != null && <strong>{title}</strong>}
+            </a>
+            {sidebarShown && (
+              <Toggle
+                aria-label="Dark mode toggle in sidebar"
+                checked={theme === 'dark'}
+                onChange={onToggleChange}
+              />
+            )}
+          </div>
+          <div className="navbar__sidebar__items">
+            <div className="menu">
+              <ul className="menu__list">
+                {links.map((linkItem, i) => (
+                  <li className="menu__list-item" key={i}>
+                    <NavLink
+                      className="menu__link"
+                      {...linkItem}
+                      onClick={hideSidebar}
+                    />
+                  </li>
+                ))}
+              </ul>
+            </div>
+          </div>
+        </div>
+      </nav>
+    </React.Fragment>
   );
 }
 
diff --git a/packages/docusaurus-theme-classic/src/theme/Navbar/styles.css b/packages/docusaurus-theme-classic/src/theme/Navbar/styles.css
new file mode 100644
index 0000000000..60132145d8
--- /dev/null
+++ b/packages/docusaurus-theme-classic/src/theme/Navbar/styles.css
@@ -0,0 +1,142 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+.react-toggle {
+  touch-action: pan-x;
+
+  display: inline-block;
+  position: relative;
+  cursor: pointer;
+  background-color: transparent;
+  border: 0;
+  padding: 0;
+
+  -webkit-touch-callout: none;
+  -webkit-user-select: none;
+  -khtml-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
+  user-select: none;
+
+  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
+  -webkit-tap-highlight-color: transparent;
+}
+
+@media screen and (max-width: 996px) {
+  .large__viewport {
+    display: none !important;
+  }
+}
+
+.react-toggle-screenreader-only {
+  border: 0;
+  clip: rect(0 0 0 0);
+  height: 1px;
+  margin: -1px;
+  overflow: hidden;
+  padding: 0;
+  position: absolute;
+  width: 1px;
+}
+
+.react-toggle--disabled {
+  cursor: not-allowed;
+  opacity: 0.5;
+  -webkit-transition: opacity 0.25s;
+  transition: opacity 0.25s;
+}
+
+.react-toggle-track {
+  width: 50px;
+  height: 24px;
+  padding: 0;
+  border-radius: 30px;
+  background-color: #4d4d4d;
+  -webkit-transition: all 0.2s ease;
+  -moz-transition: all 0.2s ease;
+  transition: all 0.2s ease;
+}
+
+.react-toggle-track-check {
+  position: absolute;
+  width: 14px;
+  height: 10px;
+  top: 0px;
+  bottom: 0px;
+  margin-top: auto;
+  margin-bottom: auto;
+  line-height: 0;
+  left: 8px;
+  opacity: 0;
+  -webkit-transition: opacity 0.25s ease;
+  -moz-transition: opacity 0.25s ease;
+  transition: opacity 0.25s ease;
+}
+
+.react-toggle--checked .react-toggle-track-check {
+  opacity: 1;
+  -webkit-transition: opacity 0.25s ease;
+  -moz-transition: opacity 0.25s ease;
+  transition: opacity 0.25s ease;
+}
+
+.react-toggle-track-x {
+  position: absolute;
+  width: 10px;
+  height: 10px;
+  top: 0px;
+  bottom: 0px;
+  margin-top: auto;
+  margin-bottom: auto;
+  line-height: 0;
+  right: 10px;
+  opacity: 1;
+  -webkit-transition: opacity 0.25s ease;
+  -moz-transition: opacity 0.25s ease;
+  transition: opacity 0.25s ease;
+}
+
+.react-toggle--checked .react-toggle-track-x {
+  opacity: 0;
+}
+
+.react-toggle-thumb {
+  transition: all 0.5s cubic-bezier(0.23, 1, 0.32, 1) 0ms;
+  position: absolute;
+  top: 1px;
+  left: 1px;
+  width: 22px;
+  height: 22px;
+  border: 1px solid #4d4d4d;
+  border-radius: 50%;
+  background-color: #fafafa;
+
+  -webkit-box-sizing: border-box;
+  -moz-box-sizing: border-box;
+  box-sizing: border-box;
+
+  -webkit-transition: all 0.25s ease;
+  -moz-transition: all 0.25s ease;
+  transition: all 0.25s ease;
+}
+
+.react-toggle--checked .react-toggle-thumb {
+  left: 27px;
+  border-color: #19ab27;
+}
+
+.react-toggle--focus .react-toggle-thumb {
+  -webkit-box-shadow: 0px 0px 3px 2px #0099e0;
+  -moz-box-shadow: 0px 0px 3px 2px #0099e0;
+  box-shadow: 0px 0px 2px 3px #0099e0;
+}
+
+.react-toggle:active:not(.react-toggle--disabled) .react-toggle-thumb {
+  -webkit-box-shadow: 0px 0px 5px 5px #0099e0;
+  -moz-box-shadow: 0px 0px 5px 5px #0099e0;
+  box-shadow: 0px 0px 5px 5px #0099e0;
+}
diff --git a/yarn.lock b/yarn.lock
index f44d02cc38..4a4b08d815 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3763,7 +3763,7 @@ class-utils@^0.3.5:
     isobject "^3.0.0"
     static-extend "^0.1.1"
 
-classnames@^2.2.6:
+classnames@^2.2.5, classnames@^2.2.6:
   version "2.2.6"
   resolved "https://registry.yarnpkg.com/classnames/-/classnames-2.2.6.tgz#43935bffdd291f326dad0a205309b38d00f650ce"
   integrity sha512-JR/iSQOSt+LQIWwrwEzJ9uk0xfN3mTVYMwt1Ir5mUcSN6pU+V4zQFFaJsclJbPuAUQH+yfWef6tm7l1quW3C8Q==
@@ -11557,6 +11557,13 @@ react-test-renderer@^16.0.0-0:
     react-is "^16.8.6"
     scheduler "^0.13.6"
 
+react-toggle@^4.0.2:
+  version "4.0.2"
+  resolved "https://registry.yarnpkg.com/react-toggle/-/react-toggle-4.0.2.tgz#77f487860efb87fafd197672a2db8c885be1440f"
+  integrity sha512-EPTWnN7gQHgEAUEmjheanZXNzY5TPnQeyyHfEs3YshaiWZf5WNjfYDrglO5F1Hl/dNveX18i4l0grTEsYH2Ccw==
+  dependencies:
+    classnames "^2.2.5"
+
 react@^16.5.0, react@^16.8.4:
   version "16.8.6"
   resolved "https://registry.yarnpkg.com/react/-/react-16.8.6.tgz#ad6c3a9614fd3a4e9ef51117f54d888da01f2bbe"