Saint-Polycarpe (French pronunciation: [sɛ̃ pɔlikaʁp] ^ⓘ) is a municipality in the Vaudreuil-Soulanges Regional County Municipality in the Montérégie region west of Montreal, Quebec, Canada, and just east of the Quebec-Ontario border. It was named for Polycarp, a 2nd-century bishop of Smyrna. The population as of the 2021 Canadian Census was 2,372.

While a parish during the 18th century, its territory included portions of what is now part of Saint-Zotique.

Settlement began around 1800 when a sawmill and a flour mill were built at the rapids of the Delisle river. In 1818, a chapel was built there and in 1830, the parish was established, called Saint-Polycarpe de la Nouvelle-Longueuil. Its post office was built in 1846.

In 1845, the Municipality of La Nouvelle-Longueuil was created, but abolished in 1847. In 1855, it was recreated out of Vaudreuil County as the Parish Municipality of Saint-Polycarpe. In 1887, the village itself split off from the surrounding rural parish to form the Village Municipality of Saint-Polycarpe.

On 31 December 1988, the parish and village merged again to form the Municipality of Saint-Polycarpe.

Based on the Dalhousie Mills station in Saint-Télesphore