Ivey played for the United States at the 2021 FIBA Under-19 World Cup in Latvia. On July 3, 2021, he scored a team-high 21 points, shooting 7-of-11 from the field, in a 83–54 group stage win over Turkey. Ivey averaged 12.3 points per game, helping his team win the gold medal, and was named to the all-tournament team.