Letnica may refer to:
- Letnica, Gdańsk, one of the quarters of the city of Gdańsk, Poland
- Letnica, Lubusz Voivodeship, a village in western Poland
- Letnica, West Pomeranian Voivodeship, a village in northwestern Poland
- Letnica, Vitina [sq], a village in the Vitina Municipality of southern Kosovo
- Letnica (river), a river of Poland