Argentina and Barcelona player Messi was also fined €2m, while his father Jorge was hit with a €1.5m fine.
Both defendants have five days to appeal but even if their guilt is confirmed, Spanish law is such that any sentence under two years for a non-violent crime rarely requires a defendant without previous convictions to serve jail time.
A spokeswoman for the court confirmed Messi was unlikely to be imprisoned.
Messi (29) and his father defrauded the Spanish tax office of almost €4.2m between 2007 and 2009 by using a web of shell companies to evade taxes on income from the player’s image rights.
The companies – with names such as Sport Consultants and Sport Enterprises – were based in tax havens such as Belize, Uruguay and Switzerland, where legislation kept the identities of their owners secret, according to the ruling.
Messi, five-times World Player of the Year, admitted during the trial to signing contracts protecting his image rights but said he had no knowledge he was partaking in any wrongdoing or defrauding the Spanish state. He said his father had control over his financial affairs, but the court said this was not enough to avoid charges.
Messi, who has held Spanish nationality since 2005, and his father had already paid €5m to the tax authorities as a “corrective” measure after formal investigations were opened.
The footballer is 10th on ‘Forbes’ magazine’s list of the world’s highest-earning athletes over the past decade, with an estimated income of €315m during this period.