Okauchee Lake is a census-designated place (CDP) in Waukesha County, Wisconsin, United States.

As of the census[2] of 2000, there were 3,916 people, 1,511 households, and 1,119 families residing in the CDP.

The racial makeup of the CDP was 98.60% White, 0.20% African American, 0.05% Native American, 0.15% Asian, 0.03% Pacific Islander, 0.26% from other races, and 0.72% from two or more races.

There were 1,511 households, out of which 33.2% had children under the age of 18 living with them, 67.0% were married couples living together, 4.4% had a female householder with no husband present, and 25.9% were non-families.

19.3% of all households were made up of individuals, and 5.6% had someone living alone who was 65 years of age or older.