Robert "Bob" Jack (4 April 1876 – 6 May 1943) was a Scottish football player and manager. Born in Alloa, Jack played in the Football League for Bolton Wanderers, Preston North End and Glossop, and the Southern League for Plymouth Argyle and Southend United. He was an outside forward. Jack is Argyle's most successful and longest-serving manager. During his 29 years in charge, the club won two league championships and established itself in the Second Division of the Football League.