1378
| Years | 
|---|
| Millennium | 
| 2nd millennium | 
| Centuries | 
| Decades | 
| Years | 
| 1378 by topic | 
|---|
| Leaders | 
| 
 | 
| Birth and death categories | 
| Births – Deaths | 
| Establishments and disestablishments categories | 
| Establishments – Disestablishments | 
| Art and literature | 
| 1378 in poetry | 
| Gregorian calendar | 1378 MCCCLXXVIII | 
| Ab urbe condita | 2131 | 
| Armenian calendar | 827 ԹՎ ՊԻԷ | 
| Assyrian calendar | 6128 | 
| Balinese saka calendar | 1299–1300 | 
| Bengali calendar | 784–785 | 
| Berber calendar | 2328 | 
| English Regnal year | 1 Ric. 2 – 2 Ric. 2 | 
| Buddhist calendar | 1922 | 
| Burmese calendar | 740 | 
| Byzantine calendar | 6886–6887 | 
| Chinese calendar | 丁巳年 (Fire Snake) 4075 or 3868 — to — 戊午年 (Earth Horse) 4076 or 3869 | 
| Coptic calendar | 1094–1095 | 
| Discordian calendar | 2544 | 
| Ethiopian calendar | 1370–1371 | 
| Hebrew calendar | 5138–5139 | 
| Hindu calendars | |
| - Vikram Samvat | 1434–1435 | 
| - Shaka Samvat | 1299–1300 | 
| - Kali Yuga | 4478–4479 | 
| Holocene calendar | 11378 | 
| Igbo calendar | 378–379 | 
| Iranian calendar | 756–757 | 
| Islamic calendar | 779–780 | 
| Japanese calendar | Eiwa 4 (永和4年) | 
| Javanese calendar | 1291–1292 | 
| Julian calendar | 1378 MCCCLXXVIII | 
| Korean calendar | 3711 | 
| Minguo calendar | 534 before ROC 民前534年 | 
| Nanakshahi calendar | −90 | 
| Thai solar calendar | 1920–1921 | 
| Tibetan calendar | 阴火蛇年 (female Fire-Snake) 1504 or 1123 or 351 — to — 阳土马年 (male Earth-Horse) 1505 or 1124 or 352 | 
Year 1378 (MCCCLXXVIII) was a common year starting on Friday of the Julian calendar.