West Okoboji Lake is a natural body of water, approximately in area, in Dickinson County in northwest Iowa in the United States. It is part of the chain of lakes known as the Iowa Great Lakes. The cities of Arnolds Park, Okoboji, West Okoboji, and Wahpeton sit on its shore. The Dakotah Indian name for the lake was Minnetonka, meaning "great waters".
Its maximum depth is , making it the deepest lake in Iowa and second in size only to Spirit Lake. The mean depth is . The drainage area of the lake is approximately .
The depth of the lake makes it a popular regional destination for motor boating, water skiing, sailing, and swimming. The lake is also a popular fishing destination in the region. The main catches in the lake are yellow perch, bluegill, and walleye. It also contains significant populations of smallmouth bass, northern pike, muskie, crappie and white bass, black bass.