Lake Nicolet (in French: lac Nicolet) is located 50 km south of Victoriaville, in the municipality of Saints-Martyrs-Canadiens, in Arthabaska Regional County Municipality (MRC), in administrative region of Centre-du-Québec, Canada.

The lake takes its name from Jean Nicolet (1598 - 1642), a French explorer at the time of New France who is known to have been the first European to explore Lake Michigan.

Lake Nicolet is 5.1 kilometres (3.2 mi) long and 1.7 kilometres (1.1 mi) wide, resembling a misshapen crescent surrounded by mountains.

The main mountain peaks around the lake are: Brûlé Mountain (500 metres (1,600 ft)) at 1.5 kilometres (0.93 mi) on the south side of the bay leading to the mouth of the lake; a 419 metres (1,375 ft) vertex on the west side and another on the southeast side (492 metres (1,614 ft)).

[1] The toponym "Lac Nicolet" was made official on December 5, 1968, at the Commission de toponymie du Québec.