Pierre Lanith Petit (15 August 1832 – 16 February 1909) was a French photographer.
Petit learned photography in Paris in the workshop of André-Adolphe-Eugène Disdéri (1819–1889) (together with 76 other employees).
In 1858, he opened his own workshop in Paris with Antoine René Trinquart, later to be called La Photographie des Deux Mondes.
This proved to be very successful and workshops were opened in Baden-Baden and Marseille (in partnership with Emile Cazalis).
Some highlights in Petit's career: Museums that hold large collections of his photographs: Websites showing photographs by Pierre Petit