Donny McCaslin (born August 11, 1966) is an American jazz saxophonist.

McCaslin's father was a vibraphonist, and he played in his father's ensemble at the age of twelve. He had his own group in high school which played three years at the Monterey Jazz Festival. He studied under Paul Contos and Brad Hecht, both of whom played in his father's group. He played in a number of youth ensembles and toured Europe and Japan with them; he was offered a full scholarship to the Berklee College of Music, where he enrolled in 1984. While there he was influenced by Gary Burton, Herb Pomeroy, Billy Pierce, George Garzone, and Joe Viola. McCaslin performed regularly in Boston and Cambridge with The True Colors Big Band, run by composer Ken Schaphorst. In 1987 he joined Burton's group and toured the world with him for four years.

In 1991 he moved to New York City and was a member of Steps Ahead until 1994, replacing Michael Brecker. He also played with the Gil Evans Orchestra, the George Gruntz Concert Jazz Band, Danilo Perez, Maria Schneider, and Santi DeBriano. In 1996 he played on Ken Schaphorst's Uprising, alongside John Medeski, Doug Yates, and Uri Caine.