diff --git a/src/components/Link.js b/src/components/Link.js
index 6639a65b..565117df 100644
--- a/src/components/Link.js
+++ b/src/components/Link.js
@@ -1,8 +1,9 @@
-import React from 'react'
+import React, { useEffect, useState } from 'react'
 import PropTypes from 'prop-types'
 import clsx from 'clsx'
 import NextJsLink from 'next/link'
 import { makeStyles } from '@material-ui/core/styles'
+import { isURLForDifferentApp, withBasePath } from 'src/utils/navigationUtils'
 
 const useStyles = makeStyles(() => ({
   anchor: {
@@ -15,10 +16,29 @@ const useStyles = makeStyles(() => ({
 const Link = (props) => {
   const { children, className, to } = props
   const classes = useStyles()
+  const [destInternal, setDestInternal] = useState(true)
+
+  // We won't always server-render the "target" prop correctly.
+  // If that causes problems, use the URL from the request when
+  // server-side rendering.
+  useEffect(() => {
+    // "When linking to other pages using next/link and next/router
+    // the basePath will be automatically applied."
+    // https://nextjs.org/docs/api-reference/next.config.js/basepath#links
+    const url = withBasePath(to)
+    if (isURLForDifferentApp(url)) {
+      setDestInternal(false)
+    }
+  }, [to])
 
   return (
     <NextJsLink href={to}>
-      <a className={clsx(classes.anchor, className)}>{children}</a>
+      <a
+        target={destInternal ? undefined : '_top'}
+        className={clsx(classes.anchor, className)}
+      >
+        {children}
+      </a>
     </NextJsLink>
   )
 }
diff --git a/src/components/__tests__/Link.test.js b/src/components/__tests__/Link.test.js
index acea53c4..5acb862a 100644
--- a/src/components/__tests__/Link.test.js
+++ b/src/components/__tests__/Link.test.js
@@ -1,14 +1,24 @@
 import React from 'react'
-import { shallow } from 'enzyme'
+import { mount, shallow } from 'enzyme'
 import NextJsLink from 'next/link'
+import { isURLForDifferentApp, withBasePath } from 'src/utils/navigationUtils'
 
 jest.mock('next/link')
 jest.mock('src/utils/urls')
+jest.mock('src/utils/navigationUtils')
 
 const getMockProps = () => ({
   children: 'hi',
   className: 'some-class',
-  to: '/some/url',
+  to: 'https://tab.gladly.io/newtab/blah/',
+})
+
+beforeEach(() => {
+  withBasePath.mockImplementation((url) => url)
+})
+
+afterEach(() => {
+  jest.clearAllMocks()
 })
 
 describe('Link component', () => {
@@ -54,4 +64,36 @@ describe('Link component', () => {
     const anchor = wrapper.childAt(0)
     expect(anchor.prop('className')).toContain('some-class-here')
   })
+
+  it('has no target prop on anchor tag by default', () => {
+    const Link = require('src/components/Link').default
+
+    const wrapper = shallow(<Link {...getMockProps()} />)
+    const anchor = wrapper.find('a').first()
+    expect(anchor.prop('target')).toBeUndefined()
+  })
+
+  it('sets target to _top for external app', () => {
+    isURLForDifferentApp.mockReturnValue(true)
+    const Link = require('src/components/Link').default
+
+    const mockProps = {
+      ...getMockProps(),
+      url: 'https://blahblah.com',
+    }
+    const wrapper = mount(<Link {...mockProps} />)
+    const anchor = wrapper.find('a').first()
+    expect(anchor.prop('target')).toEqual('_top')
+  })
+
+  it('includes the base path when calling isURLForDifferentApp', () => {
+    const Link = require('src/components/Link').default
+    withBasePath.mockImplementation((url) => `/my-base-path${url}`)
+    const mockProps = {
+      ...getMockProps(),
+      to: '/my/thing',
+    }
+    mount(<Link {...mockProps} />)
+    expect(isURLForDifferentApp).toHaveBeenCalledWith(`/my-base-path/my/thing`)
+  })
 })
diff --git a/src/utils/__tests__/navigation.test.js b/src/utils/__tests__/navigation.test.js
index 79e40b39..2c069c7e 100644
--- a/src/utils/__tests__/navigation.test.js
+++ b/src/utils/__tests__/navigation.test.js
@@ -1,9 +1,9 @@
 /* globals window */
 import { isServerSide } from 'src/utils/ssr'
-import { withBasePath } from 'src/utils/urls'
+import { withBasePath } from 'src/utils/navigationUtils'
 
 jest.mock('src/utils/ssr')
-jest.mock('src/utils/urls')
+jest.mock('src/utils/navigationUtils')
 
 // Strategy for testing against `window.location`:
 // https://www.benmvp.com/blog/mocking-window-location-methods-jest-jsdom/
diff --git a/src/utils/__tests__/navigationUtils.test.js b/src/utils/__tests__/navigationUtils.test.js
new file mode 100644
index 00000000..b4cee120
--- /dev/null
+++ b/src/utils/__tests__/navigationUtils.test.js
@@ -0,0 +1,131 @@
+import setWindowLocation from 'src/utils/testHelpers/setWindowLocation'
+
+beforeAll(() => {
+  process.env.REACT_APP_WEBSITE_PROTOCOL = 'https'
+})
+
+afterEach(() => {
+  jest.clearAllMocks()
+  jest.resetModules()
+})
+
+describe('isURLForDifferentApp', () => {
+  it('[absolute URL] is *not* a different app when the URL is absolute with the same domain and a "newtab" path', () => {
+    const { isURLForDifferentApp } = require('src/utils/navigationUtils')
+    setWindowLocation({
+      host: 'example.com',
+      hostname: 'example.com',
+      href: 'https://example.com/newtab/path/',
+      origin: 'https://example.com',
+      pathname: '/newtab/path/',
+      port: '',
+      protocol: 'https:',
+      search: '',
+    })
+    expect(isURLForDifferentApp('https://example.com/newtab/path/')).toBe(false)
+  })
+
+  it('[absolute URL] is a different app when the URL is absolute with a different domain', () => {
+    const { isURLForDifferentApp } = require('src/utils/navigationUtils')
+    setWindowLocation({
+      host: 'example.com',
+      hostname: 'example.com',
+      href: 'https://example.com/newtab/path/',
+      origin: 'https://example.com',
+      pathname: '/newtab/path/',
+      port: '',
+      protocol: 'https:',
+      search: '',
+    })
+    expect(isURLForDifferentApp('https://foo.com/newtab/path/')).toBe(true)
+  })
+
+  it('[absolute URL] is a different app when the URL is absolute and on the same domain but with a non-"newtab" app subpath', () => {
+    const { isURLForDifferentApp } = require('src/utils/navigationUtils')
+    setWindowLocation({
+      host: 'example.com',
+      hostname: 'example.com',
+      href: 'https://example.com/newtab/path/',
+      origin: 'https://example.com',
+      pathname: '/newtab/path/',
+      port: '',
+      protocol: 'https:',
+      search: '',
+    })
+    expect(isURLForDifferentApp('https://example.com/something/path/')).toBe(
+      true
+    )
+  })
+
+  it('[relative URL] is *not* a different app if the URL is exactly the same with a "newtab" subpath', () => {
+    const { isURLForDifferentApp } = require('src/utils/navigationUtils')
+    setWindowLocation({
+      host: 'example.com',
+      hostname: 'example.com',
+      href: 'https://example.com/newtab/path/',
+      origin: 'https://example.com',
+      pathname: '/newtab/path/',
+      port: '',
+      protocol: 'https:',
+      search: '',
+    })
+    expect(isURLForDifferentApp('/newtab/path/')).toBe(false)
+  })
+
+  it('[relative URL] is *not* a different app if the URL has a "newtab" subpath', () => {
+    const { isURLForDifferentApp } = require('src/utils/navigationUtils')
+    setWindowLocation({
+      host: 'example.com',
+      hostname: 'example.com',
+      href: 'https://example.com/newtab/thing/',
+      origin: 'https://example.com',
+      pathname: '/newtab/thing/',
+      port: '',
+      protocol: 'https:',
+      search: '',
+    })
+    expect(isURLForDifferentApp('/newtab/foobar/')).toBe(false)
+  })
+})
+
+describe('isAbsoluteURL', () => {
+  it('works as expected', () => {
+    const { isAbsoluteURL } = require('src/utils/navigationUtils')
+
+    // Relative URLs
+    expect(isAbsoluteURL('')).toBe(false)
+    expect(isAbsoluteURL('/')).toBe(false)
+    expect(isAbsoluteURL('/some/path')).toBe(false)
+    expect(isAbsoluteURL('localhost:3000')).toBe(false)
+
+    // Absolute URLs
+    expect(isAbsoluteURL('https://example.com/blah/path/')).toBe(true)
+    expect(isAbsoluteURL('http://example.com/blah/path/')).toBe(true)
+    expect(isAbsoluteURL('https://example.com')).toBe(true)
+    expect(isAbsoluteURL('http://localhost:3000')).toBe(true)
+  })
+})
+
+describe('withBasePath', () => {
+  beforeEach(() => {
+    process.env.NEXT_PUBLIC_URLS_BASE_PATH = '/some-path'
+  })
+
+  it('adds the basePath, when it is defined, to a relative URL', () => {
+    const { withBasePath } = require('src/utils/navigationUtils')
+    expect(withBasePath('/my-url')).toEqual('/some-path/my-url')
+  })
+
+  it('does not add the basePath, when it is not defined, to a relative URL', () => {
+    delete process.env.NEXT_PUBLIC_URLS_BASE_PATH
+    const { withBasePath } = require('src/utils/navigationUtils')
+    expect(withBasePath('/my-url')).toEqual('/my-url')
+  })
+
+  it('does not add the basePath to an absolute URL', () => {
+    const { withBasePath } = require('src/utils/navigationUtils')
+    expect(withBasePath('https://example.com/my-url')).toEqual(
+      'https://example.com/my-url'
+    )
+  })
+})
diff --git a/src/utils/navigation.js b/src/utils/navigation.js
index fda8a917..78969707 100644
--- a/src/utils/navigation.js
+++ b/src/utils/navigation.js
@@ -1,7 +1,7 @@
 /* globals window */
 import Router from 'next/router'
 import { isServerSide } from 'src/utils/ssr'
-import { withBasePath } from 'src/utils/urls'
+import { withBasePath } from 'src/utils/navigationUtils'
 
 // Handle redirects on both the client side and server side.
 // Adapted from:
diff --git a/src/utils/navigationUtils.js b/src/utils/navigationUtils.js
new file mode 100644
index 00000000..c4cc6c25
--- /dev/null
+++ b/src/utils/navigationUtils.js
@@ -0,0 +1,32 @@
+/* globals window */
+export const isAbsoluteURL = (url) =>
+  !!(url.startsWith('http://') || url.startsWith('https://'))
+
+// Base path set in Next config. This must match our app's
+// CloudFront routing.
+const basePath = process.env.NEXT_PUBLIC_URLS_BASE_PATH || ''
+
+export const withBasePath = (url) =>
+  isAbsoluteURL(url) ? url : `${basePath}${url}`
+
+/**
+ * Determine whether a URL is for a different app from the current
+ * URL. In other words, navigating to the new URL cannot simply
+ * navigate within a single-page app.
+ * @param {String} newURL - The URL to test
+ * @return {Boolean} Whether the new URL is for another app
+ */
+export const isURLForDifferentApp = (newURL) => {
+  const newURLObj = new URL(newURL, window.location.origin)
+
+  // If the URLs are on different domains, they're different apps.
+  if (newURLObj.hostname !== window.location.hostname) {
+    return true
+  }
+
+  // If the new URL is not on the "newtab" subpath, it is a
+  // different app.
+  const APP_SUBPATH = 'newtab'
+  const newURLFirstSubpath = newURLObj.pathname.split('/')[1]
+  return newURLFirstSubpath !== APP_SUBPATH
+}
diff --git a/src/utils/testHelpers/__tests__/setWindowLocation.test.js b/src/utils/testHelpers/__tests__/setWindowLocation.test.js
new file mode 100644
index 00000000..6534e167
--- /dev/null
+++ b/src/utils/testHelpers/__tests__/setWindowLocation.test.js
@@ -0,0 +1,11 @@
+/* globals window */
+
+test('setWindowLocation modifies the window.location object', () => {
+  const setWindowLocation = require('src/utils/testHelpers/setWindowLocation')
+    .default
+  expect(window.location.hostname).not.toEqual('foo.com')
+  setWindowLocation({
+    hostname: 'foo.com',
+  })
+  expect(window.location.hostname).toEqual('foo.com')
+})
diff --git a/src/utils/testHelpers/setWindowLocation.js b/src/utils/testHelpers/setWindowLocation.js
new file mode 100644
index 00000000..167d662d
--- /dev/null
+++ b/src/utils/testHelpers/setWindowLocation.js
@@ -0,0 +1,19 @@
+/* globals window */
+
+/**
+ * Change the window.location object, merging with existing values.
+ * @param {Object} modifiedLocation - An object with any values
+ *   to modify on the window.location object.
+ * @return {undefined}
+ */
+const setWindowLocation = (modifiedLocation) => {
+  const windowLocation = JSON.stringify(window.location)
+  delete window.location
+  Object.defineProperty(window, 'location', {
+    value: { ...JSON.parse(windowLocation), ...modifiedLocation },
+    configurable: true,
+    writable: true,
+  })
+}
+
+export default setWindowLocation
diff --git a/src/utils/urls.js b/src/utils/urls.js
index 7edabecd..3d4c6528 100644
--- a/src/utils/urls.js
+++ b/src/utils/urls.js
@@ -1,4 +1,5 @@
 import ensureValuesAreDefined from 'src/utils/ensureValuesAreDefined'
+import { withBasePath } from 'src/utils/navigationUtils'
 
 try {
   ensureValuesAreDefined([
@@ -12,10 +13,6 @@ try {
   )
 }
 
-// Base path set in Next config. This must match our app's
-// CloudFront routing.
-const basePath = process.env.NEXT_PUBLIC_URLS_BASE_PATH || ''
-
 // In CloudFront, the /v4 base path routes to this Next.js
 // app. The /newtab base paths routes to the this app -OR-
 // the legacy static app, depending on cookie settings. Thus,
@@ -32,8 +29,6 @@ const addTrailingSlashIfNeeded = (path) => {
   return `${path}${!hasTrailingSlash && useTrailingSlash ? '/' : ''}`
 }
 
-export const withBasePath = (path) => `${basePath}${path}`
-
 // For /api/* paths.
 const createAPIURL = (url) =>
   addTrailingSlashIfNeeded(`${NEXT_PUBLIC_URLS_API_BASE_PATH}${url}`)