Bob Stoops, the longest-tenured coach in college football, announced on Wednesday that will retire after 18 seasons at Oklahoma.
Offensive coordinator Lincoln Riley, 33, will succeed the 56-year-old Stoops, who will remain as special assistant to the athletic director.
"After 18 years at the University of Oklahoma, I've decided to step down as the head football coach," Stoops said in a statement. "... I feel the timing is perfect to hand over the reins. The program is in tremendous shape. We have outstanding players and coaches and are poised to make another run at a Big 12 and national championship.
"... Thank you all for a lifetime of memories we shared together of 10 conference championships, the 2000 national championship, strong relationships with players and coaches, and the great Oklahoma football fans. Boomer!"
Riley has produced top-10 offenses in each of his two years in Norman, Okla.
Signed to a three-year contract extension last month, Riley is not expected to receive an interim tag upon being named head coach, FOX Sports reported.
Riley takes over a team led by senior quarterback and Heisman Trophy hopeful Baker Mayfield.
"The time is now because Lincoln Riley will provide a seamless transition as the new head coach, capitalizing on an excellent staff that is already in place and providing familiarity and confidence for our players," Stoops said in the statement. "Now is simply the ideal time for me and our program to make this transition."
Stoops replaced John Blake and joined the Sooners as a rookie head coach in 1999, guiding the team to a 13-2 victory over No. 2 Florida State to win the BCS National Championship Game the following year.
Oklahoma wasn't as fortunate in its next three national title games, losing to LSU (2004), USC (2005) and Florida (2009).
The Sooners are 9-9 in bowl games under Stoops' watch, including a 35-19 triumph over Auburn in the Sugar Bowl last year.
Oklahoma captured 10 Big 12 titles under Stoops and recorded double-digit victory totals in 14 seasons, including an 11-2 mark in 2016.
A two-time Walter Camp Coach of the Year (2000, 2003), Stoops began his coaching career as a volunteer coach and graduate assistant at Iowa. He later accepted assistant coaching positions at Kent State, Kansas State and Florida, where he was part of the Gators' national championship team in 1997.