McLaughlin improved her 400-meter hurdles best to 55.28 at the 2015 national youth trials; the time was an age 15 world best, and ranked second on the all-time world youth list behind Leslie Maxie's world youth best (and national high school record) of 55.20 set in 1984. She qualified for the 2015 IAAF World Youth Championships in Cali, Colombia, where she won gold in 55.94; she finished the year as the world youth and junior leader in the event.