Saint-Étienne-de-Beauharnois (French pronunciation: [sɛ̃t‿etjɛn də boaʁnwa]) is a municipality of Quebec, Canada, located within the Beauharnois-Salaberry Regional County Municipality in the Montérégie administrative region.

In 1852, residents of the Saint-Clément and Saint-Louis parishes petitioned the Archbishop of Montreal for the creation of a new parish, which was granted after land was offered in the new settlement for a church.

[5] Its post office opened in 1865, and two years later, on January 1, 1867, the municipality was established out of territory from Saint-Clément (since 1957 part of Beauharnois) and Saint-Louis-de-Gonzague.

It was named after Saint Stephen and Beauharnois County in which it is located.

On October 26, 1869, it changed statutes and became the Parish Municipality of Saint-Etienne.