Thailand was nominated on Monday to replace the barred Iranians, the Asian Football Confederation (AFC) said on its website.
“FIFA decreed that the wearing of Islamic hijab was not in accordance with the laws of the game,” the Asian governing body said in a statement.
Iran's national Olympic committee had called on FIFA, football's world governing body, and the International Olympic Committee to review the head scarf ban. The hijab is worn by girls and women to observe Islamic dress code.
FIFA secretary general Jerome Valcke rejected the Iranian Olympic panel's request in a letter to the national football federation.
“Taking into consideration the clear position stated by the (Olympic committee) of Iran, the FIFA Executive Committee had no choice but to take the decision that (Iran) will not be able to participate,” Valcke said, according to the AFC.
FIFA maintains football's international rule book which contains a section on players' on-field equipment.
Law 4 states that “basic compulsory equipment must not have any political, religious or personal statements.
“The team of a player whose basic compulsory equipment has political, religious or personal slogans or statements will be sanctioned by the competition organizer or by FIFA.” The hijab issue was first examined in 2007 after an 11-year-old girl in Canada was prevented from wearing one for safety reasons.
FIFA's rules-making arm, the International Football Association Board, declined to make an exception for religious clothing.
Iran was scheduled to compete in a six-nation tournament for girls at the inaugural Youth Olympics being held Aug.
12-25 in Singapore.
Thailand will now represent Asia against Turkey, Equatorial Guinea, Trinidad and Tobago, Chile and Papua New Guinea.
Around 3,600 athletes aged 14-18 will compete in 26 sports.
