In March 2013, Warholm won eight gold medals in the Norwegian Youth Indoors Championships. In June at the 2013 Bislett Games, he competed in the 200 m. He finished seventh in his heat with a time of 22.25 s. Usain Bolt won a different heat at the same meet with a time of 19.79 s. At the 2013 World Youth Championships in July, he won gold in the boys' octathlon with 6451 points, a personal best.