in U.S. history, any Southerner who supported the federal plan of Reconstruction after the Civil War or who joined with the black freedman and the carpetbagger (q.v.) in support of Republican Party policies. The term is pejorative.

Scalawags came from various segments of Southern society. In the Deep South many were apt to be former Whigs of the planter–merchant aristocracy. In the upper South they were often hill-country farmers whose sympathies during the war had been Unionist. Altogether, during the Reconstruction era, scalawags constituted perhaps 20 percent of the white electorate, a sizable force in any election or constitutional convention.

The origin of the term is unclear, but it was known in the United States from at least the 1840s, at first denoting a worthless farm animal and then denoting a worthless person.