Ralph Peterson Jr. (May 20, 1962 – March 1, 2021) was an American jazz drummer and bandleader.

Four of Peterson’s uncles and his grandfather were drummers. Peterson himself began on percussion at age three. He was raised in Pleasantville, where he played trumpet at Pleasantville High School and worked locally in funk groups. He applied to Livingston College at Rutgers University to study drums, but he failed the percussion entrance exam and enrolled as a trumpeter instead, graduating in 1984.

In 1983, he joined Art Blakey‘s Jazz Messengers as the group’s second drummer for several years. He worked with Terence Blanchard and Donald Harrison in 1984, and with Walter Davis (1985, 1989), Tom Harrell (1985), Out of the Blue (1985–1988), Branford Marsalis (1986), David Murray, Craig Harris (1987), James Spaulding (1988), Roy Hargrove (1989), Jon Faddis (1989), Dewey Redman, Mark Helias (1989), and Wynton Marsalis (with the Count Basie ghost band).