The Petit lac Saint-François (in English: Little Lake Saint François) is a lake located near the municipality of Saint-Joseph-de-Coleraine in the administrative region of Chaudière-Appalaches, in Quebec, in Canada.

It receives the waters of the Ashberham River which has its source in Caribou Lake.

The discharge of the lake joins the Grand lac Saint François, source of the Saint-François River which joins the Saint Lawrence River.

An Abenaki reserve of 2,722 acres (11 km2) which was named Colraine Reserve was granted in 1853 in range #10 and range #11 west of the lake shore.

The Bécancour Trail (Abenaki Becancour Trail), passed by there, linked the Bécancour River and the basin of the Saint-François river.