Arthur R. Barker (June 4, 1899 – January 13, 1939) was an American criminal, the son of Ma Barker and a member of the Barker-Karpis gang, founded by his brother Fred Barker and Alvin Karpis. Arthur, generally known as "Doc", was typically called on for violent action, while Fred and Karpis planned the gang's crimes. He was arrested and convicted of kidnapping in 1935.