Frazier and Clint Moseley had been competing for the starting nod.
"After a complete and thorough evaluation during spring practice and through the first three-plus weeks of camp, Kiehl Frazier has earned the starting job at quarterback," coach Gene Chizik said in a statement. "We expect Kiehl to be a leader for this team and to continue to work hard every day. I am confident in his ability and leadership skills and look forward to watching him progress in both areas."
Frazier was used mostly as a Wildcat quarterback as a freshman, going 5-of-12 passing with a couple of interceptions.
Moseley, a six-game starter, has been limited since the spring by a sore throwing shoulder.
Information from The Associated Press was used in this report.