The Fiat 16-20 HP was introduced by the Italian manufacturer Fiat in 1903. The car was built in several versions:
- 1st series in 1903, wheelbase of 2,120 mm (83.5 in) and a 4-cylinder 4179 cc engine - 20 hp - produced 100 copies,
- 2nd series in 1904, became the 16-24 HP, wheelbase increased to 2,585 mm (101.8 in) and 4179 cc engine had now 24 hp - produced 130 copies.
- 3rd series in 1905, it reverts to 16-20 HP with a wheelbase increased to 2,853 mm (112.3 in) - produced 171 copies.
- 4th series in 1906, with a new 4503 cc engine - produced 290 copies.