Gregory Derayle Buckner (born September 16, 1976) is an American former professional basketball player who last played for the Memphis Grizzlies of the NBA. Selected in the second round (53rd overall) of the 1998 NBA Draft by the Dallas Mavericks after playing college basketball at Clemson, he played for the Mavericks, Philadelphia 76ers, Denver Nuggets, Minnesota Timberwolves and Memphis Grizzlies with a career scoring average of 5.0 points per game. Buckner's first professional experience came with the Grand Rapids Hoops of the Continental Basketball Association (CBA), where he averaged 8.6 points and 3.9 rebounds per game in the 1998-99 season.

After playing with the Mavericks from 1999 to 2002, Buckner signed with the 76ers as a free agent. He was waived after two seasons with the 76ers, then signed with the Denver Nuggets. In 2006, he re-signed with the Dallas Mavericks, but after one season, he was traded to the Timberwolves for Trenton Hassell on September 28, 2007. In June 2008, the Timberwolves traded him to the Memphis Grizzlies with Marko Jaric and Antoine Walker for Kevin Love, Mike Miller, Brian Cardinal and Jason Collins.

On July 9, 2009, Buckner was traded to the Dallas Mavericks as a part of the four-team deal among Grizzlies, Mavericks, Orlando Magic and Toronto Raptors.

On September 14, 2009, Buckner was waived by the Dallas Mavericks to make room for James Singleton who accepted the Mavs' qualifying offer.

On July 29, 2011, he joined the Houston Rockets as a player development coach, and he currently serves the team as an assistant coach. Buckner has reached the playoffs three times with the team as part of the coaching staff.