diff --git a/CHANGELOG.md b/CHANGELOG.md
index 364199503e..c62c4c7a5a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,8 @@
 ### Client
 - Enhance: MFMでルビを振れるように
 	- 例: `$[ruby 三須木 みすき]`
+- Enhance: MFMでUNIX時間を指定して日時を表示できるように
+	- 例: `$[unixtime 1701356400]`
 - Enhance: プラグインでエラーが発生した場合のハンドリングを強化
 - Enhance: 細かなUIのブラッシュアップ
 - Fix: 効果音が再生されるとデバイスで再生している動画や音声が停止する問題を修正 #12339
diff --git a/locales/index.d.ts b/locales/index.d.ts
index 968334e31b..6baed91c42 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -1948,6 +1948,15 @@ export interface Locale {
         "yearsAgo": string;
         "invalid": string;
     };
+    "_timeIn": {
+        "seconds": string;
+        "minutes": string;
+        "hours": string;
+        "days": string;
+        "weeks": string;
+        "months": string;
+        "years": string;
+    };
     "_time": {
         "second": string;
         "minute": string;
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 5b1d0d62bd..e59a550df5 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -1853,6 +1853,15 @@ _ago:
   yearsAgo: "{n}年前"
   invalid: "ありません"
 
+_timeIn:
+  seconds: "{n}秒後"
+  minutes: "{n}分後"
+  hours: "{n}時間後"
+  days: "{n}日後"
+  weeks: "{n}週間後"
+  months: "{n}ヶ月後"
+  years: "{n}年後"
+
 _time:
   second: "秒"
   minute: "分"
diff --git a/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts b/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
index 163724a386..b10a12b504 100644
--- a/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
+++ b/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
@@ -7,6 +7,7 @@ import { VNode, h } from 'vue';
 import * as mfm from 'mfm-js';
 import * as Misskey from 'misskey-js';
 import MkUrl from '@/components/global/MkUrl.vue';
+import MkTime from '@/components/global/MkTime.vue';
 import MkLink from '@/components/MkLink.vue';
 import MkMention from '@/components/MkMention.vue';
 import MkEmoji from '@/components/global/MkEmoji.vue';
@@ -249,6 +250,19 @@ export default function(props: MfmProps) {
 							return h('ruby', {}, [...genEl(token.children.slice(0, token.children.length - 1), scale), h('rt', text.trim())]);
 						}
 					}
+					case 'unixtime': {
+						const child = token.children[0];
+						const unixtime = parseInt(child.type === 'text' ? child.props.text : '');
+						return h('span', {
+							style: 'display: inline-block; font-size: 90%; border: solid 1px var(--divider); border-radius: 999px; padding: 4px 10px 4px 6px;',
+						}, [
+							h('i', {
+								class: 'ti ti-clock',
+								style: 'margin-right: 0.25em;',
+							}),
+							h(MkTime, { time: unixtime * 1000, mode: 'detail' }),
+						]);
+					}
 				}
 				if (style == null) {
 					return h('span', {}, ['$[', token.props.name, ' ', ...genEl(token.children, scale), ']']);
diff --git a/packages/frontend/src/components/global/MkTime.vue b/packages/frontend/src/components/global/MkTime.vue
index 5ba13ca3f3..61e65a8dcf 100644
--- a/packages/frontend/src/components/global/MkTime.vue
+++ b/packages/frontend/src/components/global/MkTime.vue
@@ -50,7 +50,15 @@ const relative = $computed<string>(() => {
 		ago >= 60 ? i18n.t('_ago.minutesAgo', { n: (~~(ago / 60)).toString() }) :
 		ago >= 10 ? i18n.t('_ago.secondsAgo', { n: (~~(ago % 60)).toString() }) :
 		ago >= -1 ? i18n.ts._ago.justNow :
-		i18n.ts._ago.future);
+		ago < -31536000 ? i18n.t('_timeIn.years', { n: Math.round(-ago / 31536000).toString() }) :
+		ago < -2592000 ? i18n.t('_timeIn.months', { n: Math.round(-ago / 2592000).toString() }) :
+		ago < -604800 ? i18n.t('_timeIn.weeks', { n: Math.round(-ago / 604800).toString() }) :
+		ago < -86400 ? i18n.t('_timeIn.days', { n: Math.round(-ago / 86400).toString() }) :
+		ago < -3600 ? i18n.t('_timeIn.hours', { n: Math.round(-ago / 3600).toString() }) :
+		ago < -60 ? i18n.t('_timeIn.minutes', { n: (~~(-ago / 60)).toString() }) :
+		ago < -10 ? i18n.t('_timeIn.seconds', { n: (~~(-ago % 60)).toString() }) :
+		'?'
+	);
 });
 
 let tickId: number;
diff --git a/packages/frontend/src/const.ts b/packages/frontend/src/const.ts
index 002c198b4d..397f804822 100644
--- a/packages/frontend/src/const.ts
+++ b/packages/frontend/src/const.ts
@@ -93,4 +93,4 @@ export const DEFAULT_SERVER_ERROR_IMAGE_URL = 'https://xn--931a.moe/assets/error
 export const DEFAULT_NOT_FOUND_IMAGE_URL = 'https://xn--931a.moe/assets/not-found.jpg';
 export const DEFAULT_INFO_IMAGE_URL = 'https://xn--931a.moe/assets/info.jpg';
 
-export const MFM_TAGS = ['tada', 'jelly', 'twitch', 'shake', 'spin', 'jump', 'bounce', 'flip', 'x2', 'x3', 'x4', 'scale', 'position', 'fg', 'bg', 'font', 'blur', 'rainbow', 'sparkle', 'rotate', 'ruby'];
+export const MFM_TAGS = ['tada', 'jelly', 'twitch', 'shake', 'spin', 'jump', 'bounce', 'flip', 'x2', 'x3', 'x4', 'scale', 'position', 'fg', 'bg', 'font', 'blur', 'rainbow', 'sparkle', 'rotate', 'ruby', 'unixtime'];