Lac-Despinassy is an unorganized territory in the Canadian province of Quebec, located within the Abitibi Regional County Municipality.

The area is east of the municipality of Saint-Dominique-du-Rosaire, north of La Morandière-Rochebaucourt and the parish municipality of Senneterre, and west of the city of Senneterre.

This name was already assigned to the area in 1911 and comes from Louis-Auguste-Victor Despinassy, a lieutenant of the Royal Artillery and Engineers Corps in General Montcalm's army.

The township is swampy, mostly forested, and flat, not exceeding 325 m (1,066 ft) above sea level.

[1] Currently, the area is being explored for potential mining of gold deposits.