Postumus Agrippa was the grandson of Roman Emperor Augustus and was named after his grandfather Marcus Agrippa.

He was always disliked and shunned by the Lady Livia, as he stood in the way of her son Tiberius succeeding to the throne after Augustus. Through her influence, Augustus too grew to dislike him and he was framed by Livia and her grandaughter Livilla for rape charges. He was banished and later killed. With his two brothers, Gaius and Lucius also killed, Tiberius was adopted as Augustus' stepson and became emperor after his death, also suspected to be attributed to his wife.