Howard Robert "Bob" Hammer (born March 3, 1930) is an American jazz pianist, composer and arranger.

Hammer studied music at Michigan State University and the Manhattan School of Music. He familiarized himself with early jazz styles (his father had performed with territory bands during the 1930s), and while living in New York, he performed with musicians such as Red Allen and Bud Freeman. During the early 1960s, he studied with composer Henry Bryant (alongside Tom McIntosh and Julian Priester).

Hammer led a band with Bob Wilber (1955). He worked in the Sauter/Finnegan Orchestra, the Roy Eldridge Quartet (1956) and with Gene Krupa (1956/57). He was a member of Red Allen’s band (1958–1962) and Eddie Condon (1959/60) Band. At that time he recorded with Charles Mingus (who called him his "Beethoven") and began to work as arranger for the bassist on Mingus Mingus Mingus Mingus Mingus, Townhall Concert and the celebrated The Black Saint and the Sinner Lady. In 1963 he played with Pee Wee Russell, Krupa and Eldridge. In 1964 he was on tour with Bobby Hackett. From 1965 to 1967 he worked as arranger for the Merv Griffin Show. He recorded with Jimmy Knepper Johnny Hartman, Woody Herman, Clark Terry and Elvin Jones. Between 1967 and 1982 he worked as a member of show bands in Las Vegas. After moving to Los Angeles in 1983, he had an engagement with Slide Hampton he worked as instructor for jazz improvisation at El Camino Community College and played in the Jimmy Cleveland Octet. He also worked with Barbara McNair, the Tommy Newsome Quartet and the MDA Labor Day Telethon. In 2004 he recorded with Floyd Standifer's quintet. He also arranged dance charts for the Nicholas Brothers, Skip Cunningham, Chester Whitmore, Jacqueline Douget, Deborah Lysholm or Tim Hickey.

Bob Hammer is a legendary jazz pianist, composer and arranger with a career spanning over 60 years and a star-studded list of collaborators. He studied music at the Manhattan School of Music and Michigan State University and early in his career, he worked with the likes of Bud Freeman, Red Allen, and Gene Krupa and in groups such as the Sauter/Finnegan Orchestra and the Roy Eldridge Quartet. This led to a musical relationship with Charles Mingus, who called him his “Beethoven” and featured him arranging bass parts on albums such as Mingus Mingus Mingus Mingus Mingus, Townhall Concert and The Black Saint and the Sinner Lady. A recording career was followed by years playing in Vegas show bands, a time as a college jazz improvisation instructor, and many other diverse arrangements. Bob Hammer plays popular and esoteric jazz classics in the style of Bud Powell, Teddy Wilson, and Nat King Cole every Sunday from 6-9 pm.