| Sizun | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Sizun (Finistere).svg |
| Coordinates: | 48.4058°N -4.0761°W |
| Elevation Min M: | 61 |
| Elevation Max M: | 382 |
| Insee: | 29277 |
| Postal Code: | 29450 |
| Arrondissement: | Morlaix |
| Canton: | Landivisiau |
| Mayor: | Catherine Le Roux[1] |
| Term: | 2023 - 2026 |
| Intercommunality: | Pays de Landivisiau |
| Area Km2: | 58.14 |
Sizun (pronounced as /fr/;) is a commune in the Finistère department of Brittany in north-western France.
Sizun has an oceanic climate (Köppen climate classification Cfb). The average annual temperature in Sizun is . The average annual rainfall is with January as the wettest month. The temperatures are highest on average in August, at around, and lowest in February, at around . The highest temperature ever recorded in Sizun was on 9 August 2003; the coldest temperature ever recorded was on 17 January 1985.
Inhabitants of Sizun are called in French Sizuniens.
In 2008, 19.74% of primary-school children attended bilingual schools.[2]