diff --git a/ui/src/app/app.tsx b/ui/src/app/app.tsx
index 7a9bfb21635bb..7b73bc50ac70c 100644
--- a/ui/src/app/app.tsx
+++ b/ui/src/app/app.tsx
@@ -8,7 +8,7 @@ import applications from './applications';
 import help from './help';
 import login from './login';
 import settings from './settings';
-import {Layout} from './shared/components/layout/layout';
+import {Layout, ThemeWrapper} from './shared/components/layout/layout';
 import {Page} from './shared/components/page/page';
 import {VersionPanel} from './shared/components/version-info/version-info-panel';
 import {AuthSettingsCtx, Provider} from './shared/context';
@@ -194,7 +194,7 @@ export class App extends React.Component<
                 <PageContext.Provider value={{title: 'Argo CD'}}>
                     <Provider value={{history, popup: this.popupManager, notifications: this.notificationsManager, navigation: this.navigationManager, baseHref: base}}>
                         <DataLoader load={() => services.viewPreferences.getPreferences()}>
-                            {pref => <div className={pref.theme ? 'theme-' + pref.theme : 'theme-light'}>{this.state.popupProps && <Popup {...this.state.popupProps} />}</div>}
+                            {pref => <ThemeWrapper theme={pref.theme}>{this.state.popupProps && <Popup {...this.state.popupProps} />}</ThemeWrapper>}
                         </DataLoader>
                         <AuthSettingsCtx.Provider value={this.state.authSettings}>
                             <Router history={history}>
diff --git a/ui/src/app/settings/components/appearance-list/appearance-list.scss b/ui/src/app/settings/components/appearance-list/appearance-list.scss
index dc70dcd77696c..44c8be678f60f 100644
--- a/ui/src/app/settings/components/appearance-list/appearance-list.scss
+++ b/ui/src/app/settings/components/appearance-list/appearance-list.scss
@@ -13,11 +13,13 @@
         }
         border-radius: 4px;
         box-shadow: 1px 2px 3px rgba(#000, 0.1);
-    }
+        & .row {
+            justify-content: space-between;
+            align-items: center;
 
-    &__button {
-        position: absolute;
-        top: 25%;
-        right: 30px;
+            .select {
+                min-width: 160px;
+            }
+        }
     }
-}
\ No newline at end of file
+}
diff --git a/ui/src/app/settings/components/appearance-list/appearance-list.tsx b/ui/src/app/settings/components/appearance-list/appearance-list.tsx
index 5e6fb06502f84..493f8bcf69ce7 100644
--- a/ui/src/app/settings/components/appearance-list/appearance-list.tsx
+++ b/ui/src/app/settings/components/appearance-list/appearance-list.tsx
@@ -1,6 +1,7 @@
 import * as React from 'react';
 import {DataLoader, Page} from '../../../shared/components';
 import {services} from '../../../shared/services';
+import {Select, SelectOption} from 'argo-ui';
 
 require('./appearance-list.scss');
 
@@ -16,16 +17,16 @@ export const AppearanceList = () => {
                     <div className='appearance-list'>
                         <div className='argo-container'>
                             <div className='appearance-list__panel'>
-                                <div className='columns'>Dark Theme</div>
-                                <div className='columns'>
-                                    <button
-                                        className='argo-button argo-button--base appearance-list__button'
-                                        onClick={() => {
-                                            const targetTheme = pref.theme === 'light' ? 'dark' : 'light';
-                                            services.viewPreferences.updatePreferences({theme: targetTheme});
-                                        }}>
-                                        {pref.theme === 'light' ? 'Enable' : 'Disable'}
-                                    </button>
+                                <div className='row'>
+                                    <span>Dark Theme</span>
+                                    <Select
+                                        value={pref.theme}
+                                        onChange={(value: SelectOption) => services.viewPreferences.updatePreferences({theme: value.value})}
+                                        options={[
+                                            {value: 'auto', title: 'Auto'},
+                                            {value: 'light', title: 'Light'},
+                                            {value: 'dark', title: 'Dark'}
+                                        ]}></Select>
                                 </div>
                             </div>
                         </div>
diff --git a/ui/src/app/shared/components/layout/layout.tsx b/ui/src/app/shared/components/layout/layout.tsx
index e08297cb4e9e6..215120f9d8380 100644
--- a/ui/src/app/shared/components/layout/layout.tsx
+++ b/ui/src/app/shared/components/layout/layout.tsx
@@ -1,6 +1,7 @@
 import * as React from 'react';
 import {Sidebar} from '../../../sidebar/sidebar';
 import {ViewPreferences} from '../../services';
+import {useTheme} from '../../utils';
 
 require('./layout.scss');
 
@@ -13,15 +14,23 @@ export interface LayoutProps {
 
 const getBGColor = (theme: string): string => (theme === 'light' ? '#dee6eb' : '#100f0f');
 
+export const ThemeWrapper = (props: {children: React.ReactNode; theme: string}) => {
+    const [systemTheme] = useTheme({
+        theme: props.theme
+    });
+    return <div className={'theme-' + systemTheme}>{props.children}</div>;
+};
+
 export const Layout = (props: LayoutProps) => {
+    const [theme] = useTheme({theme: props.pref.theme});
     React.useEffect(() => {
-        if (props.pref.theme) {
-            document.body.style.background = getBGColor(props.pref.theme);
+        if (theme) {
+            document.body.style.background = getBGColor(theme);
         }
-    }, [props.pref.theme]);
+    }, [theme]);
 
     return (
-        <div className={props.pref.theme ? 'theme-' + props.pref.theme : 'theme-light'}>
+        <div className={`theme-${theme}`}>
             <div className={'cd-layout'}>
                 <Sidebar onVersionClick={props.onVersionClick} navItems={props.navItems} pref={props.pref} />
                 <div className={`cd-layout__content ${props.pref.hideSidebar ? 'cd-layout__content--sb-collapsed' : 'cd-layout__content--sb-expanded'} custom-styles`}>
diff --git a/ui/src/app/shared/components/monaco-editor.tsx b/ui/src/app/shared/components/monaco-editor.tsx
index a30381638f0b5..e0a34a06e9440 100644
--- a/ui/src/app/shared/components/monaco-editor.tsx
+++ b/ui/src/app/shared/components/monaco-editor.tsx
@@ -2,6 +2,7 @@ import * as React from 'react';
 
 import * as monacoEditor from 'monaco-editor';
 import {services} from '../services';
+import {getTheme, useSystemTheme} from '../utils';
 
 export interface EditorInput {
     text: string;
@@ -28,10 +29,25 @@ const MonacoEditorLazy = React.lazy(() =>
     import('monaco-editor').then(monaco => {
         const Component = (props: MonacoProps) => {
             const [height, setHeight] = React.useState(0);
+            const [theme, setTheme] = React.useState('dark');
+
+            React.useEffect(() => {
+                const destroySystemThemeListener = useSystemTheme(systemTheme => {
+                    if (theme === 'auto') {
+                        monaco.editor.setTheme(systemTheme === 'dark' ? 'vs-dark' : 'vs');
+                    }
+                });
+
+                return () => {
+                    destroySystemThemeListener();
+                };
+            }, [theme]);
 
             React.useEffect(() => {
                 const subscription = services.viewPreferences.getPreferences().subscribe(preferences => {
-                    monaco.editor.setTheme(preferences.theme === 'dark' ? 'vs-dark' : 'vs');
+                    setTheme(preferences.theme);
+
+                    monaco.editor.setTheme(getTheme(preferences.theme) === 'dark' ? 'vs-dark' : 'vs');
                 });
 
                 return () => {
diff --git a/ui/src/app/shared/components/version-info/version-info-panel.tsx b/ui/src/app/shared/components/version-info/version-info-panel.tsx
index 8622b762c8a5a..15edf463aae73 100644
--- a/ui/src/app/shared/components/version-info/version-info-panel.tsx
+++ b/ui/src/app/shared/components/version-info/version-info-panel.tsx
@@ -2,6 +2,7 @@ import {DataLoader, SlidingPanel, Tooltip} from 'argo-ui';
 import * as React from 'react';
 import {VersionMessage} from '../../models';
 import {services} from '../../services';
+import {ThemeWrapper} from '../layout/layout';
 
 interface VersionPanelProps {
     isShown: boolean;
@@ -26,14 +27,14 @@ export class VersionPanel extends React.Component<VersionPanelProps, {copyState:
                     <DataLoader load={() => this.props.version}>
                         {version => {
                             return (
-                                <div className={'theme-' + pref.theme}>
+                                <ThemeWrapper theme={pref.theme}>
                                     <SlidingPanel header={this.header} isShown={this.props.isShown} onClose={() => this.props.onClose()} hasCloseButton={true} isNarrow={true}>
                                         <div className='argo-table-list'>{this.buildVersionTable(version)}</div>
                                         <div>
                                             <Tooltip content='Copy all version info as JSON'>{this.getCopyButton(version)}</Tooltip>
                                         </div>
                                     </SlidingPanel>
-                                </div>
+                                </ThemeWrapper>
                             );
                         }}
                     </DataLoader>
diff --git a/ui/src/app/shared/utils.ts b/ui/src/app/shared/utils.ts
index c57715a8f933d..129b8e769a951 100644
--- a/ui/src/app/shared/utils.ts
+++ b/ui/src/app/shared/utils.ts
@@ -1,3 +1,5 @@
+import React from 'react';
+
 export function hashCode(str: string) {
     let hash = 0;
     for (let i = 0; i < str.length; i++) {
@@ -34,3 +36,71 @@ export function isValidURL(url: string): boolean {
         }
     }
 }
+
+export const colorSchemes = {
+    light: '(prefers-color-scheme: light)',
+    dark: '(prefers-color-scheme: dark)'
+};
+
+/**
+ * quick method to check system theme
+ * @param theme auto, light, dark
+ * @returns dark or light
+ */
+export function getTheme(theme: string) {
+    if (theme !== 'auto') {
+        return theme;
+    }
+
+    const dark = window.matchMedia(colorSchemes.dark);
+
+    return dark.matches ? 'dark' : 'light';
+}
+
+/**
+ * create a listener for system theme
+ * @param cb callback for theme change
+ * @returns destroy listener
+ */
+export const useSystemTheme = (cb: (theme: string) => void) => {
+    const dark = window.matchMedia(colorSchemes.dark);
+    const light = window.matchMedia(colorSchemes.light);
+
+    const listener = () => {
+        cb(dark.matches ? 'dark' : 'light');
+    };
+
+    dark.addEventListener('change', listener);
+    light.addEventListener('change', listener);
+
+    return () => {
+        dark.removeEventListener('change', listener);
+        light.removeEventListener('change', listener);
+    };
+};
+
+export const useTheme = (props: {theme: string}) => {
+    const [theme, setTheme] = React.useState(getTheme(props.theme));
+
+    React.useEffect(() => {
+        let destroyListener: (() => void) | undefined;
+
+        // change theme by system, only register listener when theme is auto
+        if (props.theme === 'auto') {
+            destroyListener = useSystemTheme(systemTheme => {
+                setTheme(systemTheme);
+            });
+        }
+
+        // change theme manually
+        if (props.theme !== theme) {
+            setTheme(getTheme(props.theme));
+        }
+
+        return () => {
+            destroyListener?.();
+        };
+    }, [props.theme]);
+
+    return [theme];
+};