Saint-Théophile (French pronunciation: [sɛ̃ teɔfil]) is a municipality in the Municipalité régionale de comté de Beauce-Sartigan in Quebec, Canada on the Canada–United States border.

It is part of the Chaudière-Appalaches region and the population is 702 as of 2021.

It is named after reverend Théophile Montminy, who had been chosen by the archdiocese to find a proper location for a church.

Saint-Théophile lies next to the border with Maine, and there is a border crossing on Route 173 within the municipality, in the hamlet of Armstrong.

The Armstrong custom office is the third in importance in Quebec.