Gregorio Fontana, born Giovanni Battista Lorenzo Fontana (7 December 1735 – 24 August 1803) was an Italian mathematician and a religious of the Piarist order.

He was chair of mathematics at the university of Pavia succeeding Roger Joseph Boscovich.

He has been credited with the introduction of polar coordinates.

[1][2] His brother was the physicist Felice Fontana (1730–1805).

This article about an Italian mathematician is a stub.