diff --git a/src/client/theme-default/components/NavBar.ts b/src/client/theme-default/components/NavBar.ts
index b0e961942cfc..e64fc5fce1e1 100644
--- a/src/client/theme-default/components/NavBar.ts
+++ b/src/client/theme-default/components/NavBar.ts
@@ -1,29 +1,14 @@
-// TODO dropdowns
 import { computed } from 'vue'
-import { useSiteData, useRoute } from 'vitepress'
-import { withBase } from '../utils'
-
-const normalizePath = (path: string): string => {
-  path = path
-    .replace(/#.*$/, '')
-    .replace(/\?.*$/, '')
-    .replace(/\.html$/, '')
-  if (path.endsWith('/')) {
-    path += 'index'
-  }
-  return path
-}
+import { useSiteData } from 'vitepress'
+import NavBarLink from './NavBarLink.vue'
 
 export default {
-  setup() {
-    const route = useRoute()
-    const isActiveLink = (link: string): boolean => {
-      return normalizePath(withBase(link)) === normalizePath(route.path)
-    }
+  components: {
+    NavBarLink
+  },
 
+  setup() {
     return {
-      withBase,
-      isActiveLink,
       navData:
         process.env.NODE_ENV === 'production'
           ? // navbar items do not change in production
diff --git a/src/client/theme-default/components/NavBar.vue b/src/client/theme-default/components/NavBar.vue
index e7af130b7ad5..5c34229d4422 100644
--- a/src/client/theme-default/components/NavBar.vue
+++ b/src/client/theme-default/components/NavBar.vue
@@ -13,16 +13,11 @@
     <span>{{ $site.title }}</span>
   </a>
   <nav class="nav-links" v-if="navData">
-    <a
-      class="nav-link"
-      v-for="{ text, link, target, rel, ariaLabel } of navData"
-      :class="{ active: isActiveLink(link) }"
-      :href="withBase(link)"
-      :target="target"
-      :rel="rel"
-      :aria-label="ariaLabel"
-      >{{ text }}</a
-    >
+    <NavBarLink
+      v-for="item of navData"
+      :key="item.link"
+      :item="item"
+    />
   </nav>
 </template>
 
@@ -44,18 +39,4 @@
 .nav-links {
   list-style-type: none;
 }
-
-.nav-link {
-  color: var(--text-color);
-  margin-left: 1.5rem;
-  font-weight: 600;
-  display: inline-block;
-  height: 1.75rem;
-  line-height: 1.75rem;
-}
-
-.nav-link:hover,
-.nav-link.active {
-  border-bottom: 2px solid var(--accent-color);
-}
 </style>
diff --git a/src/client/theme-default/components/NavBarLink.ts b/src/client/theme-default/components/NavBarLink.ts
new file mode 100644
index 000000000000..973fd48044a6
--- /dev/null
+++ b/src/client/theme-default/components/NavBarLink.ts
@@ -0,0 +1,78 @@
+// TODO dropdowns
+import { defineComponent, computed, PropType } from 'vue'
+import { useRoute } from 'vitepress'
+import { withBase, isExternal } from '../utils'
+import { DefaultTheme } from '../config'
+import OutboundLink from './icons/OutboundLink.vue'
+
+const normalizePath = (path: string): string => {
+  path = path
+    .replace(/#.*$/, '')
+    .replace(/\?.*$/, '')
+    .replace(/\.html$/, '')
+  if (path.endsWith('/')) {
+    path += 'index'
+  }
+  return path
+}
+
+export default defineComponent({
+  components: {
+    OutboundLink
+  },
+
+  props: {
+    item: {
+      type: Object as PropType<DefaultTheme.NavItemWithLink>,
+      required: true
+    }
+  },
+
+  setup(props) {
+    const item = props.item
+
+    const route = useRoute()
+
+    const classes = computed(() => ({
+      active: isActiveLink.value,
+      external: isExternalLink.value
+    }))
+
+    const isActiveLink = computed(() => {
+      return normalizePath(withBase(item.link)) === normalizePath(route.path)
+    })
+
+    const isExternalLink = computed(() => {
+      return isExternal(item.link)
+    })
+
+    const href = computed(() => {
+      return isExternalLink.value ? item.link : withBase(item.link)
+    })
+
+    const target = computed(() => {
+      if (item.target) {
+        return item.target
+      }
+
+      return isExternalLink.value ? '_blank' : ''
+    })
+
+    const rel = computed(() => {
+      if (item.rel) {
+        return item.rel
+      }
+
+      return isExternalLink.value ? 'noopener noreferrer' : ''
+    })
+
+    return {
+      classes,
+      isActiveLink,
+      isExternalLink,
+      href,
+      target,
+      rel
+    }
+  }
+})
diff --git a/src/client/theme-default/components/NavBarLink.vue b/src/client/theme-default/components/NavBarLink.vue
new file mode 100644
index 000000000000..4a5f57caed4e
--- /dev/null
+++ b/src/client/theme-default/components/NavBarLink.vue
@@ -0,0 +1,35 @@
+<template>
+  <a
+    class="nav-link"
+    :class="classes"
+    :href="href"
+    :target="target"
+    :rel="rel"
+    :aria-label="item.ariaLabel"
+  >
+    {{ item.text }}
+    <OutboundLink v-if="isExternalLink" />
+  </a>
+</template>
+
+<script src="./NavBarLink"></script>
+
+<style>
+.nav-link {
+  color: var(--text-color);
+  margin-left: 1.5rem;
+  font-weight: 600;
+  display: inline-block;
+  height: 1.75rem;
+  line-height: 1.75rem;
+}
+
+.nav-link:hover,
+.nav-link.active {
+  border-bottom: 2px solid var(--accent-color);
+}
+
+.nav-link.external:hover {
+  border-bottom: 0;
+}
+</style>
diff --git a/src/client/theme-default/components/icons/OutboundLink.vue b/src/client/theme-default/components/icons/OutboundLink.vue
new file mode 100644
index 000000000000..06f8ba08b093
--- /dev/null
+++ b/src/client/theme-default/components/icons/OutboundLink.vue
@@ -0,0 +1,31 @@
+<template functional>
+  <svg
+    class="icon outbound"
+    xmlns="http://www.w3.org/2000/svg"
+    aria-hidden="true"
+    x="0px"
+    y="0px"
+    viewBox="0 0 100 100"
+    width="15"
+    height="15"
+  >
+    <path
+      fill="currentColor"
+      d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"
+    />
+    <polygon
+      fill="currentColor"
+      points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"
+    />
+  </svg>
+</template>
+
+<style>
+.icon.outbound {
+  color: #aaa;
+  display: inline-block;
+  vertical-align: middle;
+  position: relative;
+  top: -1px;
+}
+</style>
diff --git a/src/client/theme-default/utils.ts b/src/client/theme-default/utils.ts
index 4c6aee47dca2..a743905817cd 100644
--- a/src/client/theme-default/utils.ts
+++ b/src/client/theme-default/utils.ts
@@ -2,11 +2,16 @@ import { useSiteData, Route } from 'vitepress'
 
 export const hashRE = /#.*$/
 export const extRE = /\.(md|html)$/
+export const outboundRE = /^[a-z]+:/i
 
 export function withBase(path: string) {
   return (useSiteData().value.base + path).replace(/\/+/g, '/')
 }
 
+export function isExternal(path: string): boolean {
+  return outboundRE.test(path)
+}
+
 export function isActive(route: Route, path?: string): boolean {
   if (path === undefined) {
     return false