diff --git a/app/components/DropdownMenu/DropdownMenu.js b/app/components/DropdownMenu/DropdownMenu.js
index c0afcb1f0..e67f5aa8e 100644
--- a/app/components/DropdownMenu/DropdownMenu.js
+++ b/app/components/DropdownMenu/DropdownMenu.js
@@ -23,6 +23,7 @@ type Props = {
   onClose?: () => void,
   children?: Children,
   className?: string,
+  hover?: boolean,
   style?: Object,
   position?: 'left' | 'right' | 'center',
 };
@@ -72,7 +73,7 @@ class DropdownMenu extends React.Component<Props> {
         this.initPosition();
 
         // attempt to keep only one flyout menu open at once
-        if (previousClosePortal) {
+        if (previousClosePortal && !this.props.hover) {
           previousClosePortal();
         }
         previousClosePortal = closePortal;
@@ -134,7 +135,7 @@ class DropdownMenu extends React.Component<Props> {
   }
 
   render() {
-    const { className, label, children } = this.props;
+    const { className, hover, label, children } = this.props;
 
     return (
       <div className={className}>
@@ -146,7 +147,14 @@ class DropdownMenu extends React.Component<Props> {
         >
           {({ closePortal, openPortal, isOpen, portal }) => (
             <React.Fragment>
-              <Label onClick={this.handleOpen(openPortal, closePortal)}>
+              <Label
+                onMouseOver={
+                  hover ? this.handleOpen(openPortal, closePortal) : undefined
+                }
+                onClick={
+                  hover ? undefined : this.handleOpen(openPortal, closePortal)
+                }
+              >
                 {label || (
                   <NudeButton
                     id={`${this.id}button`}
@@ -216,6 +224,7 @@ const Position = styled.div`
   z-index: 1000;
   transform: ${props =>
     props.position === 'center' ? 'translateX(-50%)' : 'initial'};
+  pointer-events: none;
 `;
 
 const Menu = styled.div`
@@ -228,6 +237,7 @@ const Menu = styled.div`
   overflow: hidden;
   overflow-y: auto;
   box-shadow: ${props => props.theme.menuShadow};
+  pointer-events: all;
 
   @media print {
     display: none;
diff --git a/app/components/DropdownMenu/DropdownMenuItem.js b/app/components/DropdownMenu/DropdownMenuItem.js
index 63c4958ee..5035d0bba 100644
--- a/app/components/DropdownMenu/DropdownMenuItem.js
+++ b/app/components/DropdownMenu/DropdownMenuItem.js
@@ -1,14 +1,22 @@
 // @flow
 import * as React from 'react';
+import { CheckmarkIcon } from 'outline-icons';
 import styled from 'styled-components';
 
 type Props = {
   onClick?: (SyntheticEvent<>) => void | Promise<void>,
   children?: React.Node,
+  selected?: boolean,
   disabled?: boolean,
 };
 
-const DropdownMenuItem = ({ onClick, children, disabled, ...rest }: Props) => {
+const DropdownMenuItem = ({
+  onClick,
+  children,
+  selected,
+  disabled,
+  ...rest
+}: Props) => {
   return (
     <MenuItem
       onClick={disabled ? undefined : onClick}
@@ -17,6 +25,9 @@ const DropdownMenuItem = ({ onClick, children, disabled, ...rest }: Props) => {
       tabIndex="-1"
       {...rest}
     >
+      {selected !== undefined && (
+        <CheckmarkIcon color={selected === false ? 'transparent' : undefined} />
+      )}
       {children}
     </MenuItem>
   );
@@ -26,6 +37,7 @@ const MenuItem = styled.a`
   display: flex;
   margin: 0;
   padding: 6px 12px;
+  width: 100%;
   height: 32px;
 
   color: ${props =>
diff --git a/app/components/Theme.js b/app/components/Theme.js
index 543a1412c..bcf9aefe8 100644
--- a/app/components/Theme.js
+++ b/app/components/Theme.js
@@ -13,7 +13,7 @@ type Props = {
 
 function Theme({ children, ui }: Props) {
   return (
-    <ThemeProvider theme={ui.theme === 'dark' ? dark : light}>
+    <ThemeProvider theme={ui.resolvedTheme === 'dark' ? dark : light}>
       <React.Fragment>
         <GlobalStyles />
         {children}
diff --git a/app/menus/AccountMenu.js b/app/menus/AccountMenu.js
index 64ec8f9ad..c95ef5712 100644
--- a/app/menus/AccountMenu.js
+++ b/app/menus/AccountMenu.js
@@ -3,7 +3,7 @@ import * as React from 'react';
 import { Link } from 'react-router-dom';
 import { observable } from 'mobx';
 import { inject, observer } from 'mobx-react';
-import { SunIcon, MoonIcon } from 'outline-icons';
+import { SunIcon, MoonIcon, EyeIcon, CheckmarkIcon } from 'outline-icons';
 import styled from 'styled-components';
 import UiStore from 'stores/UiStore';
 import AuthStore from 'stores/AuthStore';
@@ -82,19 +82,42 @@ class AccountMenu extends React.Component<Props> {
             Report a bug
           </DropdownMenuItem>
           <hr />
-          <DropdownMenuItem onClick={ui.toggleDarkMode}>
-            <ChangeTheme justify="space-between">
-              {isLightTheme ? (
-                <React.Fragment>
-                  Dark theme <MoonIcon />
-                </React.Fragment>
-              ) : (
-                <React.Fragment>
-                  Light theme <SunIcon />
-                </React.Fragment>
-              )}
-            </ChangeTheme>
-          </DropdownMenuItem>
+          <DropdownMenu
+            hover
+            position="right"
+            style={{
+              left: 170,
+              position: 'relative',
+              top: -34,
+            }}
+            label={
+              <DropdownMenuItem>
+                <ChangeTheme justify="space-between">
+                  Appearance
+                  {ui.resolvedTheme === 'light' ? <SunIcon /> : <MoonIcon />}
+                </ChangeTheme>
+              </DropdownMenuItem>
+            }
+          >
+            <DropdownMenuItem
+              onClick={() => ui.setTheme('system')}
+              selected={ui.theme === 'system'}
+            >
+              System
+            </DropdownMenuItem>
+            <DropdownMenuItem
+              onClick={() => ui.setTheme('light')}
+              selected={ui.theme === 'light'}
+            >
+              Light
+            </DropdownMenuItem>
+            <DropdownMenuItem
+              onClick={() => ui.setTheme('dark')}
+              selected={ui.theme === 'dark'}
+            >
+              Dark
+            </DropdownMenuItem>
+          </DropdownMenu>
           <hr />
           <DropdownMenuItem onClick={this.handleLogout}>
             Log out
diff --git a/app/stores/UiStore.js b/app/stores/UiStore.js
index 9d9533546..0b75c1eea 100644
--- a/app/stores/UiStore.js
+++ b/app/stores/UiStore.js
@@ -9,7 +9,8 @@ import type { Toast } from '../types';
 const UI_STORE = 'UI_STORE';
 
 class UiStore {
-  @observable theme: 'light' | 'dark';
+  @observable theme: 'light' | 'dark' | 'system';
+  @observable systemTheme: 'light' | 'dark';
   @observable activeModalName: ?string;
   @observable activeModalProps: ?Object;
   @observable activeDocumentId: ?string;
@@ -29,9 +30,19 @@ class UiStore {
       // no-op Safari private mode
     }
 
+    let colorSchemeQueryList = window.matchMedia(
+      '(prefers-color-scheme: dark)'
+    );
+    const setSystemTheme = event => {
+      this.systemTheme = event.matches ? 'dark' : 'light';
+    };
+
+    setSystemTheme(colorSchemeQueryList);
+    colorSchemeQueryList.addListener(setSystemTheme);
+
     // persisted keys
     this.tocVisible = data.tocVisible;
-    this.theme = data.theme || 'light';
+    this.theme = data.theme || 'system';
 
     autorun(() => {
       try {
@@ -43,8 +54,8 @@ class UiStore {
   }
 
   @action
-  toggleDarkMode = () => {
-    this.theme = this.theme === 'dark' ? 'light' : 'dark';
+  setTheme = (theme: 'light' | 'dark' | 'system') => {
+    this.theme = theme;
 
     if (window.localStorage) {
       window.localStorage.setItem('theme', this.theme);
@@ -153,6 +164,15 @@ class UiStore {
     this.toasts.delete(id);
   };
 
+  @computed
+  get resolvedTheme(): 'dark' | 'light' {
+    if (this.theme === 'system') {
+      return this.systemTheme;
+    }
+
+    return this.theme;
+  }
+
   @computed
   get orderedToasts(): Toast[] {
     return orderBy(Array.from(this.toasts.values()), 'createdAt', 'desc');