1091
| Years | 
|---|
| Millennium | 
| 2nd millennium | 
| Centuries | 
| Decades | 
| Years | 
| 1091 by topic | 
|---|
| Leaders | 
| 
 | 
| Birth and death categories | 
| Births – Deaths | 
| Establishments and disestablishments categories | 
| Establishments – Disestablishments | 
| Gregorian calendar | 1091 MXCI | 
| Ab urbe condita | 1844 | 
| Armenian calendar | 540 ԹՎ ՇԽ | 
| Assyrian calendar | 5841 | 
| Balinese saka calendar | 1012–1013 | 
| Bengali calendar | 497–498 | 
| Berber calendar | 2041 | 
| English Regnal year | 4 Will. 2 – 5 Will. 2 | 
| Buddhist calendar | 1635 | 
| Burmese calendar | 453 | 
| Byzantine calendar | 6599–6600 | 
| Chinese calendar | 庚午年 (Metal Horse) 3788 or 3581 — to — 辛未年 (Metal Goat) 3789 or 3582 | 
| Coptic calendar | 807–808 | 
| Discordian calendar | 2257 | 
| Ethiopian calendar | 1083–1084 | 
| Hebrew calendar | 4851–4852 | 
| Hindu calendars | |
| - Vikram Samvat | 1147–1148 | 
| - Shaka Samvat | 1012–1013 | 
| - Kali Yuga | 4191–4192 | 
| Holocene calendar | 11091 | 
| Igbo calendar | 91–92 | 
| Iranian calendar | 469–470 | 
| Islamic calendar | 483–484 | 
| Japanese calendar | Kanji 5 (寛治5年) | 
| Javanese calendar | 995–996 | 
| Julian calendar | 1091 MXCI | 
| Korean calendar | 3424 | 
| Minguo calendar | 821 before ROC 民前821年 | 
| Nanakshahi calendar | −377 | 
| Seleucid era | 1402/1403 AG | 
| Thai solar calendar | 1633–1634 | 
| Tibetan calendar | 阳金马年 (male Iron-Horse) 1217 or 836 or 64 — to — 阴金羊年 (female Iron-Goat) 1218 or 837 or 65 | 
Year 1091 (MXCI) was a common year starting on Wednesday of the Julian calendar.