Sumner is a town in Oxford County, Maine, United States. Sumner is included in the Lewiston-Auburn, Maine metropolitan New England city and town area. The population was 994 at the 2020 census. The town includes the villages of West Sumner and East Sumner.

Oxford County is a county in the state of Maine, United States. As of the 2020 Census, the county had a population of 57,777. Its county seat is the town of Paris. The county was formed on March 4, 1805, by the Massachusetts General Court in the Maine District from northerly portions of York and Cumberland counties. It borders the Canadian province of Quebec. Part of Oxford County is included in the Lewiston-Auburn, Maine metropolitan New England City and Town Area while a different part of Oxford County is included in the Portland-South Portland-Biddeford, Maine metropolitan New England City and Town Area.