Oconomowoc Lake is a village in Waukesha County, Wisconsin, United States. The population was 566 at the 2020 census. Located just outside the City of Oconomowoc, the village includes the residential area encircling Oconomowoc Lake. The area became known as a summer retreat for wealthy residents of Milwaukee and Chicago at the turn of the 20th century and has remained one of the wealthiest municipalities in Wisconsin.