Tonga participated at the 2018 Summer Youth Olympics in Buenos Aires, Argentina from 6 October to 18 October 2018.
The following is the list of number of competitors that participated at the Games per sport.
Tonga was given a spot to compete in the girl's event by the tripartite committee, but Tonga did not compete in archery.
Tonga was given a spot to compete by the tripartite committee.
Tonga qualified in the girls' tournament by finishing runner's up at the 2017 OFC Youth Futsal Tournament and after New Zealand decided to compete in rugby sevens.
Tonga was given a quota to compete in the boy's event by the tripartite committee.
Tonga was given a quota to compete in the girls' +63 kg event by the tripartite committee, but Tonga did not compete in taekwondo.