The two gold medals went to 12th grader Nguyen Tuan Phong from Bac Ninh Province, and 11th grader Vo Hoang Hai from Hanoi.
Two silver medals were won by 12th grader Nguyen Tuan Duong of Hai Phong City and 12th grader Le Viet Hoang Anh of Thanh Hoa Province.
12th grader Phan The Manh from Bac Ninh won a bronze medal.
IPhO 2023 is considered the biggest of its kind as it has attracted 398 students from 84 countries and territories across the world.
The awards ceremony was held on Monday morning.