Iran had suffered a narrow 81-77 defeat to Japan in the 24th FIBA Asia U-18 Championship in July 25 but it defeated Japan on Sunday and became champion for the third time.
Iran won its first FIBA Asia U18 crown in 2008.
Iran, Japan and Korea claimed first, second and third place respectively at the 2016 FIBA Asia U18 Championship.
The competition was held in Tehran, Iran from July 22 to 31.
The twelve participating teams have been into groups of two as follows:
Group A: China, Chinese Taipei, the Philippines, India, Iraq, Thailand.
Group B: Iran, South Korea, Japan, Kazakhstan, Indonesia, Lebanon.
The top four teams from each group will advance to the Quarter-Final.
The top three teams from the 24th FIBA Asia U-18 Championship will represent Asia at the 2017 FIBA U-19 World Championship.