Manchester United remained the Premier League's richest club by revenue in 2018-19 but could lose their status if they don't qualify for the Champions League again this season.
Barcelona topped the list for the first time with more than 800 million euros ($NZ1.3 billion) with Real Madrid second and United third, on 711 million euros ($NZ1.19 billion).
Five Premier League sides are in the top 10, with Manchester City sixth, Liverpool seventh, Tottenham Hotspur eighth and Chelsea ninth.
In the 23rd edition of the list, compiled by Deloitte, United top the Premier League sides again but their income is forecast to drop in 2019-20 because of their failure to qualify for the Champions League.
Should they fail again this season, Deloitte said, they could be overtaken by Premier League champions Manchester City and European champions Liverpool.
Combined revenues of the top 20 teams grew 11 per cent to 9.3 billion euros ($NZ15.6 billion), a record, Deloitte said.