Hayneville is a town in Lowndes County, Alabama, United States and its county seat. At the 2010 census the population was 932, down from its record high of 1,177 in 2000. It is also part of the Montgomery Metropolitan Statistical Area. It initially incorporated in 1831, but lapsed, finally reincorporating in 1967. Before 1970, the town appeared only twice on the U.S. Census: in 1850 and 1890. The 1850 estimate of 800 residents ranked it as the largest town in the county at the time.

Lowndes County is in the central part of the U.S. state of Alabama. As of the 2020 census, the county's population was 10,311. Its county seat is Hayneville. The county is named in honor of William Lowndes, a member of the United States Congress from South Carolina.