In October Önder competed at the World Championships where he won silver on parallel bars behind Joe Fraser.

Önder competed at the Baku World Cup; however the competition was canceled after qualifications due to the COVID-19 pandemic.

At the 2020 Olympic Games Önder qualified to both the all-around and vault event finals where he finished twenty-fourth and seventh respectively.

Individually he won silver on floor exercise behind Nicola Bartolini and bronze on horizontal bar behind Marios Georgiou and Adem Asil.

Önder next competed at the Islamic Solidarity Games where he helped Turkey once again win gold in the team event.