Brašanac was a regular member of the Serbia national under-17 team. He also represented Serbia at the 2011 UEFA Under-19 Championship. They reached the semi-final of the tournament and were eliminated from the competition by the Czech Republic. In early 2013, Brašanac made his debut for the Serbia U21s and immediately became a regular member of the team. He scored his first goal for the under-21 side in a 3–0 away win over Belgium on 5 March 2014. Brašanac was also a member of the final squad at the 2015 UEFA Under-21 Championship.