The Martin OMJM 20th Anniversary John Mayer Signature acoustic-electric guitar commemorates the 20th anniversary of John Mayer’s popular OM-28JM model. It exhibits the same versatility for today's diverse contemporary musical styles and includes John Mayer’s electronic signature. Additional appointments to the OMJM include an Engelmann spruce top, East Indian rosewood back and sides, an ebony fingerboard and bridge, nickel open-gear tuners and Fishman Gold Plus Natural I electronics.

The Martin OMJM 20th comes with a hardshell case.

This model was only produced in 2023.