Fábio Jr., stage name of Fábio Corrêa Ayrosa Galvão (São Paulo, November 21, 1953), is a Brazilian singer, composer, multi-instrumentalist and actor.

Fábio Jr. began performing in São Paulo as a child on TV (Bandeirantes) and radio shows. In 1971, he adopted the stage name Uncle Jack and later Mark Davis, under which he recorded several singles sung in English, having success with "Don't Let Me Try" and "I Want to Be Free Again.