Rice Lake is a lake in south-eastern Ontario south of Peterborough, Ontario. The lake is part of the Trent-Severn Waterway, which connects to the lake by the Otonabee and Trent Rivers. The lake is 32 km long and 5 km wide.

A drumlin field is located northwest of the lake and the lake's islands are partially submerged drumlins.

This lake is fairly shallow and was named for the wild rice which grew in it and was harvested by native people of the area. Prehistoric burial mounds are found at Serpent Mounds Park on the north shore of the lake. In the late 19th century, steamboats provided passenger service on the lake. Most of the extensive stands of wild rice originally found in the lake were wiped out when water levels were raised in the lake during the construction of the waterway.