The Court of Arbitration, to which Ronaldo appealed, "orders Juventus Turin to pay the sum of 9,774,166.66 euros", plus interest and procedural costs, it stated in its decision.
The sum equates to the difference between the salary actually received by Ronaldo and that which he should have received after tax and other deductions.
Ronaldo, who spent three seasons in Italy with Juventus before joining Manchester United in 2021 and then Saudi club Al Nassr, was claiming 19.5 million euros (£16.7m) but the arbitration panel reduced that by 50 per cent.
Contacted by AFP, Juventus declined to comment, but said it would be issuing a statement "shortly".
According to the rankings drawn up by the American business magazine Forbes, the five-time Ballon d'Or winner was the world's highest-paid sportsman in 2023, with $136 million (£109.2m), including $46 million (£37m) in wages.
Juventus, who are listed on the stock exchange, recorded losses of 123.7 million euros (£106m) in the 2022/23 financial year, which ran to the end of June, it announced in October.
No provision has been made in the accounts of Italian football's most successful club, currently third in Serie A, for the payment of this wages backlog.
