Robert J. Mayo (August 25, 1951 – February 23, 2004) was an American session keyboardist and guitarist, perhaps best known for his work with Peter Frampton.

In 1971, Mayo formed Doc Holliday with Frank Carillo, Tom Arlotta, and Bob Liggio.

He then left RRC, was replaced with Mark Hitt and teamed up with Peter Frampton and joined his touring band.

In 1981, Mayo was asked by Joey Kramer of Aerosmith to play keyboards in his band Renegade, fronted by vocalist Marge Raymond.

In 1983, Mayo played keyboards on Aerosmith's first tour in three years, in support of their Rock in a Hard Place album, also adding background vocals.