In 2015, Okon George set a new PB of 50.76s in the 400 m at the Resisprint meeting in the Swiss city of La Chaux-de-Fonds. This was her first time under the 51s barrier. At the 2015 World Championships in Athletics, she equalled her PB in the semi-finals of the women's 400 m after posting a time of 50.87 s to qualify third fastest in her heat. Later on in the year at the All Africa Games, she won a silver medal behind Kabange Mupopo in a new personal best of 50.71 s.