Fifa has fined the Lao Football Federation $700,000 for sanctioning the illegal transfer of minors.
The fine comes after BBC Sport reported in 2015 that African players as young as 14 were being traded to Laos - in contravention of Fifa rules.
Fifa deemed that the federation had breached "several provisions concerning the international transfer and first registration of minor players".
The BBC's investigation started after FIFPro highlighted the issue.
The global players' union had learned that top Laos side Champasak United had imported 23 under-age players from West Africa to an unregistered football academy in February 2015.
In a clear breach of Fifa rules, the club then fielded overseas players as young as 14 and 15 in league games.
Fifa regulations prohibit the movement of players to a foreign club or academy until they are 18 unless certain restrictions reply.