Colby Don Carthel (born August 29, 1976) is an American football coach who is the head coach at Stephen F. Austin State University, a position he has held since December 2018. Colby's first head coaching stint was at Texas A&M University-Commerce where he won the Division II National Championship in 2017. Previous to his time as head coach, he was the defensive coordinator for his father and former West Texas A&M University head coach, Don Carthel, from 2006 to 2012. He played college football at Angelo State University where he was an all-conference linebacker.