Tosa can refer to:
- Japanese terms:
- Geography:
- In Kōchi Prefecture
- Tosa, Kōchi (city)
- Tosa, Kōchi (town), a town
- Tosa District, Kōchi
- Tosa province or Tosa Domain, now known as Kōchi Prefecture
- In Kōchi Prefecture
- Tosa dialect
- Tosa school of painting, represented by:
- Tosa Mitsunobu
- Tosa Mitsuoki
- Tosa-mi, or tataki, a cooking technique
- A Japanese surname, e.g.:
- Reiko Tosa, marathon runner
- Kunihiko Tosa, karateka
- Tosa (dog)
- Tosa class battleship
- The Sharp Zaurus model SL-6000
- Geography:
- Two mountains in Europe:
- Cima Tosa, a peak in the Brenta Dolomites
- La Tosa in the Pyrenees
- Wauwatosa, Wisconsin
- The Tosa corner or hairpin of the San Marino Grand Prix race track
- The TOSA Foundation