Lac Grand is a lake in the Outaouais region of Quebec, Canada.

It covers an area of about 377 hectares and lies at an elevation of 160 m (520 ft) above sea level.

The lake consists of four main bays, two in the south, two in the north.

The main section of the lake is where it reaches its deepest depths, going as deep as 40 metres below the surface, which is slightly deeper than significantly larger Lake Winnipeg.

There are many islands in Lac Grand, the largest being Ile-Des-Peres in Priest's Bay.