| Pierre Lorain | |
| Birth Date: | April 21, 1942 |
| Birth Place: | Farnham, Quebec |
| Death Date: | December 24, 2004 |
| Party: | Quebec Liberal Party |
| Office1: | Member of the National Assembly of Quebec for Saint-Jean |
| Term Start1: | 1985 |
| Term End1: | 1989 |
| Predecessor1: | Jérôme Proulx |
| Successor1: | Michel Charbonneau |
Pierre Lorrain (April 21, 1942 – December 24, 2004) was a lawyer and political figure in Quebec. He represented Saint-Jean in the Quebec National Assembly from 1985 to 1989 as a Liberal.
He was born in Farnham, Quebec, the son of Roch Lorrain and Jeanne Marcil, and was educated at the Collège Roussin and the . Lorrain was admitted to the Quebec bar in 1973 and practised law in Saint-Jean-sur-Richelieu.
He was president and founder of the Haut-Richelieu Tourism bureau. Lorrain served as President of the National Assembly from 1985 to 1989. He did not run for reelection in 1989. In that year, he was named Quebec delegate-general to Brussels. Lorrain served as president of the Quebec Legal Services commission from 1994 to 1999 and for the Municipal commission from 1999 to 2004.
Lorrain died in Saint-Jean-sur-Richelieu at the age of 62. He was survived by his wife, Johanne Desrochers.