South Gull Lake is an unincorporated community in Ross Township, Kalamazoo County in the U.S. state of Michigan. It is a Census-designated place (CDP) used for statistical purposes and does not have any legal status as an incorporated municipality. The population was 1,526 at the 2000 census.
The CDP includes an area around the southern and eastern shores of Gull Lake. The lake extends into Richland Township to the west and the northern tip crosses into Barry County. Although the entire area surrounding the lake is developed, in the 2000 Census the CDP is limited to Ross Township. The CDP includes the communities known locally as Yorkville at , Gull Lake at , and Midland Park at . A summer post office named Yorkville operated from 1917-1939.