Marc Mann is an American keyboardist, guitarist, programmer, arranger and conductor. He has a Master's Degree in Music from UCLA.

He is known for his work with Oingo Boingo, Jeff Lynne and Electric Light Orchestra. In 2002 he performed in the "Concert for George" alongside Eric Clapton, Jeff Lynne, Ringo Starr and Paul McCartney, playing George Harrison's parts.
He is credited as performer, arranger or producer on 54 albums. Mann is a long time collaborator with Danny Elfman in such films as the Men in Black series, Mars Attacks!, Sleepy Hollow, plus many more. He is usually credited for MIDI supervision and some orchestrations.

In addition, he has written string arrangements for several artists, including System Of A Down, Red Hot Chili Peppers, Regina Spektor and George Harrison's son Dhani Harrison's band Thenewno2.

He played for the Electric Light Orchestra on their tour for the promotion of their album Zoom. Mann played rhythm guitar and lead on some tracks and also keyboards. However the tour was cancelled.

Mann played briefly for Oingo Boingo (another collaboration with Elfman) playing the keyboards at some gigs such as Live from the Universal Amphitheatre.

In January 1994, Mann had been hired by Jeff Lynne to help clean a few of John Lennon's cassettes, that the remaining Beatles Paul McCartney, George Harrison and Ringo Starr finished and turned a few songs into Beatles songs. In 2002, Mann made string arrangements for several songs on Harrison's posthumous Brainwashed album.