diff --git a/gulpfile.ts b/gulpfile.ts
index 85305cd0e..a518e0d47 100644
--- a/gulpfile.ts
+++ b/gulpfile.ts
@@ -47,7 +47,14 @@ gulp.task('build:copy:views', () =>
 	gulp.src('./src/server/web/views/**/*').pipe(gulp.dest('./built/server/web/views'))
 );
 
-gulp.task('build:copy', gulp.parallel('build:copy:views', () =>
+gulp.task('build:copy:plugins', () =>
+	gulp.src([
+		'./src/plugins/**/*',
+		'!./src/plugins/**/*.ts'
+	]).pipe(gulp.dest('./built/plugins'))
+);
+
+gulp.task('build:copy', gulp.parallel('build:copy:views', 'build:copy:plugins', () =>
 	gulp.src([
 		'./src/const.json',
 		'./src/server/web/views/**/*',
diff --git a/src/boot/index.ts b/src/boot/index.ts
index 2c86d8ed8..9532e6694 100644
--- a/src/boot/index.ts
+++ b/src/boot/index.ts
@@ -21,11 +21,11 @@ export default async function() {
 	process.title = `Misskey (${cluster.isMaster ? 'master' : 'worker'})`;
 
 	if (cluster.isMaster || program.disableClustering) {
-		await masterMain();
-
 		if (cluster.isMaster) {
 			ev.mount();
 		}
+
+		await masterMain();
 	}
 
 	if (cluster.isWorker || program.disableClustering) {
diff --git a/src/boot/master.ts b/src/boot/master.ts
index 6c23a528f..2e97e5fe1 100644
--- a/src/boot/master.ts
+++ b/src/boot/master.ts
@@ -1,3 +1,4 @@
+import * as path from 'path';
 import * as os from 'os';
 import * as cluster from 'cluster';
 import chalk from 'chalk';
@@ -12,6 +13,7 @@ import * as pkg from '../../package.json';
 import { program } from '../argv';
 import { showMachineInfo } from '../misc/show-machine-info';
 import { initDb } from '../db/postgre';
+import Xev from 'xev';
 
 const logger = new Logger('core', 'cyan');
 const bootLogger = logger.createSubLogger('boot', 'magenta', false);
@@ -75,6 +77,10 @@ export async function masterMain() {
 		await spawnWorkers(config.clusterLimit);
 	}
 
+	loadPlugins();
+
+	bootLogger.succ('All plugins loaded');
+
 	if (!program.noDaemons) {
 		require('../daemons/server-stats').default();
 		require('../daemons/notes-stats').default();
@@ -109,6 +115,24 @@ function showEnvironment(): void {
 	logger.info(`You ${isRoot() ? '' : 'do not '}have root privileges`);
 }
 
+const pluginService = {
+	registerTheme(theme: any) {
+		const ev = new Xev();
+		ev.emit('registerPluginTheme', theme);
+	}
+};
+
+function loadPlugins(): void {
+	const plugins = [
+		path.resolve(`${__dirname}/../plugins/featured-themes`)
+	];
+	for (const plugin of plugins) {
+		const pluginMeta = require(`${plugin}/plugin-meta.json`);
+		bootLogger.info(`Plugin loaded: ${pluginMeta.name} v${pluginMeta.version}`);
+		require(`${plugin}/main.js`).onActivate(pluginService);
+	}
+}
+
 /**
  * Init app
  */
diff --git a/src/boot/worker.ts b/src/boot/worker.ts
index 362fa3f26..d7b453d4c 100644
--- a/src/boot/worker.ts
+++ b/src/boot/worker.ts
@@ -1,5 +1,9 @@
 import * as cluster from 'cluster';
 import { initDb } from '../db/postgre';
+import Xev from 'xev';
+import { registerTheme } from '../pluginThemes';
+
+const ev = new Xev();
 
 /**
  * Init worker process
@@ -16,5 +20,9 @@ export async function workerMain() {
 	if (cluster.isWorker) {
 		// Send a 'ready' message to parent process
 		process.send!('ready');
+
+		ev.on('registerPluginTheme', theme => {
+			registerTheme(theme);
+		});
 	}
 }
diff --git a/src/client/app/common/views/components/settings/theme.vue b/src/client/app/common/views/components/settings/theme.vue
index 3e6b9133c..4de0b5345 100644
--- a/src/client/app/common/views/components/settings/theme.vue
+++ b/src/client/app/common/views/components/settings/theme.vue
@@ -93,7 +93,7 @@
 			<summary><fa icon="folder-open"/> {{ $t('manage-themes') }}</summary>
 			<ui-select v-model="selectedThemeId" :placeholder="$t('select-theme')">
 				<optgroup :label="$t('builtin-themes')">
-					<option v-for="x in builtinThemes" :value="x.id" :key="x.id">{{ x.name }}</option>
+					<option v-for="x in presetThemes" :value="x.id" :key="x.id">{{ x.name }}</option>
 				</optgroup>
 				<optgroup :label="$t('my-themes')">
 					<option v-for="x in installedThemes.filter(t => t.author == this.$store.state.i.username)" :value="x.id" :key="x.id">{{ x.name }}</option>
@@ -113,7 +113,7 @@
 					<span>{{ $t('theme-code') }}</span>
 				</ui-textarea>
 				<ui-button @click="export_()" link :download="`${selectedTheme.name}.misskeytheme`" ref="export"><fa icon="box"/> {{ $t('export') }}</ui-button>
-				<ui-button @click="uninstall()" v-if="!builtinThemes.some(t => t.id == selectedTheme.id)"><fa :icon="['far', 'trash-alt']"/> {{ $t('uninstall') }}</ui-button>
+				<ui-button @click="uninstall()" v-if="!presetThemes.some(t => t.id == selectedTheme.id)"><fa :icon="['far', 'trash-alt']"/> {{ $t('uninstall') }}</ui-button>
 			</template>
 		</details>
 	</section>
@@ -123,7 +123,7 @@
 <script lang="ts">
 import Vue from 'vue';
 import i18n from '../../../../i18n';
-import { lightTheme, darkTheme, builtinThemes, applyTheme, Theme } from '../../../../theme';
+import { lightTheme, darkTheme, applyTheme, Theme } from '../../../../theme';
 import { Chrome } from 'vue-color';
 import * as uuid from 'uuid';
 import * as tinycolor from 'tinycolor2';
@@ -138,7 +138,8 @@ export default Vue.extend({
 
 	data() {
 		return {
-			builtinThemes: builtinThemes,
+			themes: [],
+			presetThemes: [],
 			installThemeCode: null,
 			selectedThemeId: null,
 			myThemeBase: 'light',
@@ -151,11 +152,17 @@ export default Vue.extend({
 		};
 	},
 
-	computed: {
-		themes(): Theme[] {
-			return builtinThemes.concat(this.$store.state.device.themes);
-		},
+	created() {
+		this.$root.getThemes().then(themes => {
+			this.themes = themes;
+		});
 
+		this.$root.getPresetThemes().then(presetThemes => {
+			this.presetThemes = presetThemes;
+		});
+	}
+
+	computed: {
 		darkThemes(): Theme[] {
 			return this.themes.filter(t => t.base == 'dark' || t.kind == 'dark');
 		},
diff --git a/src/client/app/init.ts b/src/client/app/init.ts
index da7baff4f..018810e59 100644
--- a/src/client/app/init.ts
+++ b/src/client/app/init.ts
@@ -16,7 +16,7 @@ import App from './app.vue';
 import checkForUpdate from './common/scripts/check-for-update';
 import MiOS from './mios';
 import { version, codename, lang, locale } from './config';
-import { builtinThemes, applyTheme, futureTheme } from './theme';
+import { applyTheme, futureTheme } from './theme';
 import Dialog from './common/views/components/dialog.vue';
 
 if (localStorage.getItem('theme') == null) {
@@ -364,28 +364,31 @@ export default (callback: (launch: (router: VueRouter) => [Vue, MiOS], os: MiOS)
 			os.store.watch(s => {
 				return s.device.darkmode;
 			}, v => {
-				const themes = os.store.state.device.themes.concat(builtinThemes);
-				const dark = themes.find(t => t.id == os.store.state.device.darkTheme);
-				const light = themes.find(t => t.id == os.store.state.device.lightTheme);
-				applyTheme(v ? dark : light);
+				os.getThemes().then(themes => {
+					const dark = themes.find(t => t.id == os.store.state.device.darkTheme);
+					const light = themes.find(t => t.id == os.store.state.device.lightTheme);
+					applyTheme(v ? dark : light);
+				});
 			});
 			os.store.watch(s => {
 				return s.device.lightTheme;
 			}, v => {
-				const themes = os.store.state.device.themes.concat(builtinThemes);
-				const theme = themes.find(t => t.id == v);
-				if (!os.store.state.device.darkmode) {
-					applyTheme(theme);
-				}
+				os.getThemes().then(themes => {
+					const theme = themes.find(t => t.id == v);
+					if (!os.store.state.device.darkmode) {
+						applyTheme(theme);
+					}
+				});
 			});
 			os.store.watch(s => {
 				return s.device.darkTheme;
 			}, v => {
-				const themes = os.store.state.device.themes.concat(builtinThemes);
-				const theme = themes.find(t => t.id == v);
-				if (os.store.state.device.darkmode) {
-					applyTheme(theme);
-				}
+				os.getThemes().then(themes => {
+					const theme = themes.find(t => t.id == v);
+					if (os.store.state.device.darkmode) {
+						applyTheme(theme);
+					}
+				});
 			});
 			//#endregion
 
@@ -447,6 +450,8 @@ export default (callback: (launch: (router: VueRouter) => [Vue, MiOS], os: MiOS)
 					api: os.api,
 					getMeta: os.getMeta,
 					getMetaSync: os.getMetaSync,
+					getThemes: os.getThemes,
+					getPresetThemes: os.getPresetThemes,
 					signout: os.signout,
 					new(vm, props) {
 						const x = new vm({
diff --git a/src/client/app/mios.ts b/src/client/app/mios.ts
index ae1446b93..1366f641d 100644
--- a/src/client/app/mios.ts
+++ b/src/client/app/mios.ts
@@ -9,6 +9,8 @@ import Progress from './common/scripts/loading';
 
 import Err from './common/views/components/connect-failed.vue';
 import Stream from './common/scripts/stream';
+import { Theme, builtinThemes } from './theme';
+import { concat } from '../../prelude/array';
 
 //#region api requests
 let spinner = null;
@@ -478,6 +480,28 @@ export default class MiOS extends EventEmitter {
 			}
 		});
 	}
+
+	/**
+	 * プリセットテーマ一覧を取得します
+	 */
+	@autobind
+	public getPresetThemes() {
+		return new Promise<Theme[]>(async (res, rej) => {
+			const pluginThemes = await this.api('plugins/themes') as Theme[];
+			res(concat([builtinThemes, pluginThemes]));
+		});
+	}
+
+	/**
+	 * テーマ一覧を取得します
+	 */
+	@autobind
+	public getThemes() {
+		return new Promise<Theme[]>(async (res, rej) => {
+			const installedThemes = this.store.state.device.themes as Theme[];
+			res(concat([await this.getPresetThemes(), installedThemes]));
+		});
+	}
 }
 
 class WindowSystem extends EventEmitter {
diff --git a/src/client/app/theme.ts b/src/client/app/theme.ts
index b16fcdff4..26c0cbf65 100644
--- a/src/client/app/theme.ts
+++ b/src/client/app/theme.ts
@@ -12,34 +12,12 @@ export type Theme = {
 
 export const lightTheme: Theme = require('../themes/light.json5');
 export const darkTheme: Theme = require('../themes/dark.json5');
-export const lavenderTheme: Theme = require('../themes/lavender.json5');
 export const futureTheme: Theme = require('../themes/future.json5');
-export const halloweenTheme: Theme = require('../themes/halloween.json5');
-export const cafeTheme: Theme = require('../themes/cafe.json5');
-export const japaneseSushiSetTheme: Theme = require('../themes/japanese-sushi-set.json5');
-export const gruvboxDarkTheme: Theme = require('../themes/gruvbox-dark.json5');
-export const monokaiTheme: Theme = require('../themes/monokai.json5');
-export const vividTheme: Theme = require('../themes/vivid.json5');
-export const rainyTheme: Theme = require('../themes/rainy.json5');
-export const mauveTheme: Theme = require('../themes/mauve.json5');
-export const grayTheme: Theme = require('../themes/gray.json5');
-export const tweetDeckTheme: Theme = require('../themes/tweet-deck.json5');
 
 export const builtinThemes = [
 	lightTheme,
 	darkTheme,
-	lavenderTheme,
 	futureTheme,
-	halloweenTheme,
-	cafeTheme,
-	japaneseSushiSetTheme,
-	gruvboxDarkTheme,
-	monokaiTheme,
-	vividTheme,
-	rainyTheme,
-	mauveTheme,
-	grayTheme,
-	tweetDeckTheme,
 ];
 
 export function applyTheme(theme: Theme, persisted = true) {
diff --git a/src/pluginThemes.ts b/src/pluginThemes.ts
new file mode 100644
index 000000000..02ca8ca43
--- /dev/null
+++ b/src/pluginThemes.ts
@@ -0,0 +1,9 @@
+const themes: any[] = [];
+
+export function registerTheme(theme: any) {
+	themes.push(theme);
+}
+
+export function getThemes() {
+	return themes;
+}
diff --git a/src/plugins/featured-themes/main.ts b/src/plugins/featured-themes/main.ts
new file mode 100644
index 000000000..2cd54a4b5
--- /dev/null
+++ b/src/plugins/featured-themes/main.ts
@@ -0,0 +1,12 @@
+require('json5/lib/register');
+import * as fs from 'fs';
+
+export function onActivate(service: any) {
+	const fileNames = fs.readdirSync(`${__dirname}/themes`)
+		.filter(f => fs.statSync(`${__dirname}/themes/${f}`).isFile());
+
+	for (const fileName of fileNames) {
+		const theme = require(`${__dirname}/themes/${fileName}`);
+		service.registerTheme(theme);
+	}
+}
diff --git a/src/plugins/featured-themes/plugin-meta.json b/src/plugins/featured-themes/plugin-meta.json
new file mode 100644
index 000000000..653aae635
--- /dev/null
+++ b/src/plugins/featured-themes/plugin-meta.json
@@ -0,0 +1,5 @@
+{
+	"misskeyVersion": "11",
+	"name": "featured-themes",
+	"version": "1.0.0"
+}
diff --git a/src/client/themes/cafe.json5 b/src/plugins/featured-themes/themes/cafe.json5
similarity index 100%
rename from src/client/themes/cafe.json5
rename to src/plugins/featured-themes/themes/cafe.json5
diff --git a/src/client/themes/gray.json5 b/src/plugins/featured-themes/themes/gray.json5
similarity index 100%
rename from src/client/themes/gray.json5
rename to src/plugins/featured-themes/themes/gray.json5
diff --git a/src/client/themes/gruvbox-dark.json5 b/src/plugins/featured-themes/themes/gruvbox-dark.json5
similarity index 100%
rename from src/client/themes/gruvbox-dark.json5
rename to src/plugins/featured-themes/themes/gruvbox-dark.json5
diff --git a/src/client/themes/halloween.json5 b/src/plugins/featured-themes/themes/halloween.json5
similarity index 100%
rename from src/client/themes/halloween.json5
rename to src/plugins/featured-themes/themes/halloween.json5
diff --git a/src/client/themes/japanese-sushi-set.json5 b/src/plugins/featured-themes/themes/japanese-sushi-set.json5
similarity index 100%
rename from src/client/themes/japanese-sushi-set.json5
rename to src/plugins/featured-themes/themes/japanese-sushi-set.json5
diff --git a/src/client/themes/lavender.json5 b/src/plugins/featured-themes/themes/lavender.json5
similarity index 100%
rename from src/client/themes/lavender.json5
rename to src/plugins/featured-themes/themes/lavender.json5
diff --git a/src/client/themes/mauve.json5 b/src/plugins/featured-themes/themes/mauve.json5
similarity index 100%
rename from src/client/themes/mauve.json5
rename to src/plugins/featured-themes/themes/mauve.json5
diff --git a/src/client/themes/monokai.json5 b/src/plugins/featured-themes/themes/monokai.json5
similarity index 100%
rename from src/client/themes/monokai.json5
rename to src/plugins/featured-themes/themes/monokai.json5
diff --git a/src/client/themes/rainy.json5 b/src/plugins/featured-themes/themes/rainy.json5
similarity index 100%
rename from src/client/themes/rainy.json5
rename to src/plugins/featured-themes/themes/rainy.json5
diff --git a/src/client/themes/tweet-deck.json5 b/src/plugins/featured-themes/themes/tweet-deck.json5
similarity index 100%
rename from src/client/themes/tweet-deck.json5
rename to src/plugins/featured-themes/themes/tweet-deck.json5
diff --git a/src/client/themes/vivid.json5 b/src/plugins/featured-themes/themes/vivid.json5
similarity index 100%
rename from src/client/themes/vivid.json5
rename to src/plugins/featured-themes/themes/vivid.json5
diff --git a/src/server/api/endpoints/plugins/themes.ts b/src/server/api/endpoints/plugins/themes.ts
new file mode 100644
index 000000000..d2fdcb155
--- /dev/null
+++ b/src/server/api/endpoints/plugins/themes.ts
@@ -0,0 +1,14 @@
+import define from '../../define';
+import { getThemes } from '../../../../pluginThemes';
+
+export const meta = {
+	desc: {
+		'ja-JP': 'プラグインによって登録されたテーマを取得します。'
+	},
+
+	tags: ['themes']
+};
+
+export default define(meta, async (ps, me) => {
+	return getThemes();
+});