| Centuries: | 3rd century · 4th century · 5th century |
| Decades: | 290s 300s 310s 320s 330s 340s 350s |
| Years: | 317 318 319 320 321 322 323 |
| 320 by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishment and disestablishment categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 320 CCCXX |
| Ab urbe condita | 1073 |
| Armenian calendar | N/A |
| Bahá'í calendar | -1524 – -1523 |
| Bengali calendar | -273 |
| Berber calendar | 1270 |
| Buddhist calendar | 864 |
| Burmese calendar | -318 |
| Byzantine calendar | 5828 – 5829 |
| Chinese calendar | 己卯年十二月初五日 (2956/3016-12-5) — to —
庚辰年十一月十五日(2957/3017-11-15) |
| Coptic calendar | 36 – 37 |
| Ethiopian calendar | 312 – 313 |
| Hebrew calendar | 4080 – 4081 |
| Hindu calendars | |
| - Bikram Samwat | 376 – 377 |
| - Shaka Samvat | 242 – 243 |
| - Kali Yuga | 3421 – 3422 |
| Holocene calendar | 10320 |
| Iranian calendar | 302 BP – 301 BP |
| Islamic calendar | 311 BH – 310 BH |
| Japanese calendar | |
| Korean calendar | 2653 |
| Thai solar calendar | 863 |