Lock's return is a coup for Missouri coach Barry Odom, who guided the Tigers to a Texas Bowl berth this season, their first bowl appearance since 2014. The Tigers, who have led the SEC in total offense each of the past two seasons, will return nine starters on offense next season.
Lock will also be playing for a new offensive coordinator. Former Tennessee head coach Derek Dooley steps in to replace Josh Heupel, who left to take the UCF head-coaching job.
"I'm very excited to be coming back for my senior year, and I'm really optimistic about what we can do as a team next season," said Lock, who passed for 3,964 yards in 2017. "There were a lot of factors that went into this decision, but the main ones include: a feeling of responsibility and loyalty to my teammates and coaches at Mizzou. We have goals to achieve together, having the chance to play for a new coach in coach Dooley, and his system that will continue to add to my development, and, of course, getting my degree."