The Fiat A.20 was an Italian aero-engine of the 1920s. It was a water-cooled V12 engine that was used by early versions of the Fiat CR.20 fighter and the Macchi M.41 seaplane.
In 1923, FIAT built the A.15, a 430 hp (320 kW) water-cooled V12 engine. While no production of the A.15 ensued, it formed the basis for the Fiat A.20, which differed in being a Monobloc engine, and delivered a similar power despite a reduction in capacity from 20.3 to 18.7 L (1,239 to 1,141 in<sup>3</sup>).