Severson is an emergency room doctor from Osceola who was first elected in 2010. He announced his decision not to run again on Monday.
Severson chaired a special task force on mental health this session which resulted in passage of more than a dozen bills designed to improve services across the state. His vice-chair on that committee, Democratic Rep. Sandy Pasch, is also not running again.
Severson continues to work at the Osceola Medical Center. He says he is looking forward to spending more time with his family.
Republicans currently hold a 60-39 majority in the Assembly. All 99 seats are up for election this November.