Sayner is an unincorporated census-designated place in the Town of Plum Lake in Vilas County, Wisconsin, United States. It is located at the intersection of Highway 155 and County N, about 15 miles northwest of Eagle River. As of the 2010 census, its population was 207. Sayner has an area of 1.828 square miles (4.73 km2); 1.826 square miles (4.73 km2) of this is land, and 0.002 square miles (0.0052 km2) is water.
Sayner is home to the Vilas County Historical Society.
Sayner is also home to one of the nation's oldest summer camps, Camp Highlands for Boys, founded in 1904, and located on the northeast end of Plum Lake.
Located on the south shore of Plum Lake, the Plum Lake Golf Course is the oldest nine-hole golf course in Wisconsin, founded in 1912.