Haliburton played for the United States at the 2019 FIBA Under-19 World Cup in Heraklion, Greece. On June 30, he scored a team-high 21 points, shooting 8–of–9 from the field, in a 102–84 group stage win over Lithuania. Haliburton averaged 7.9 points and 6.9 assists per game, shooting 69 percent from the field. He led the United States to a gold medal and was named to the all-tournament team.