| Millennium: | 2nd millennium | 
|---|---|
| Centuries: | |
| Decades: | |
| Years: | 
| Gregorian calendar | 1521 MDXXI | 
| Ab urbe condita | 2274 | 
| Armenian calendar | 970 ԹՎ ՋՀ | 
| Assyrian calendar | 6271 | 
| Balinese saka calendar | 1442–1443 | 
| Bengali calendar | 928 | 
| Berber calendar | 2471 | 
| English Regnal year | 12 Hen. 8 – 13 Hen. 8 | 
| Buddhist calendar | 2065 | 
| Burmese calendar | 883 | 
| Byzantine calendar | 7029–7030 | 
| Chinese calendar | 庚辰年 (Metal Dragon) 4217 or 4157 — to — 辛巳年 (Metal Snake) 4218 or 4158 | 
| Coptic calendar | 1237–1238 | 
| Discordian calendar | 2687 | 
| Ethiopian calendar | 1513–1514 | 
| Hebrew calendar | 5281–5282 | 
| Hindu calendars | |
| - Vikram Samvat | 1577–1578 | 
| - Shaka Samvat | 1442–1443 | 
| - Kali Yuga | 4621–4622 | 
| Holocene calendar | 11521 | 
| Igbo calendar | 521–522 | 
| Iranian calendar | 899–900 | 
| Islamic calendar | 927–928 | 
| Japanese calendar | Eishō 18 / Daiei 1 (大永元年) | 
| Javanese calendar | 1438–1439 | 
| Julian calendar | 1521 MDXXI | 
| Korean calendar | 3854 | 
| Minguo calendar | 391 before ROC 民前391年 | 
| Nanakshahi calendar | 53 | 
| Thai solar calendar | 2063–2064 | 
Year 1521 (MDXXI) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar.
March–April: Ferdinand Magellan's voyage around the world.
May 25: Martin Luther outlawed.
Hans Maler zu Schwaz, Portrait of a beardless man with the inscription:
„ALS MAN. 1521. ZALT. WAS. ICH. 33. IAR ALT“
(mutatis mutandis to English: „as we had in 1521, I was 33 years old)
Lorenzo Lotto, Christ Taking Leave of his Mother