Donald Edward Gullett (January 6, 1951 – February 14, 2024) was an American professional baseball player and coach. He played in Major League Baseball as a left-handed pitcher from 1970 through 1978. He was a member of the Cincinnati Reds Big Red Machine dynasty that won four National League pennants and two World Series championships between 1970 and 1976. Gullett was also a member of the New York Yankees teams that won two consecutive World Series championships in 1977 and 1978.
After his playing career, Gullett served as pitching coach for the Reds from 1993 to 2005. In 2002, he was inducted into the Cincinnati Reds Hall of Fame.