Barcelona striker has been found guilty of breaching three tax offences, which total around £3.5million in the years 2007, 2008 and 2009.
Spain Supreme Court ratifies Lionel Messi’s prison sentence after appeal
While he also failed to declare around £8.7m in image rights.
However, as Spanish law denotes that an sentence under two years can be served as probation, Messi is unlikely to spend any time in jail.
His father Jorge was also given a 21-month sentence, but his has been reduced to 15.
However, he will be forced to pay a fine of around £1.7m.
Jorge Messi was originally ordered to pay a fine of £1.3m, but that has been reduced to £1.1m.
The five-time Ballon d’Or winner’s team-mates, Neymar and Javier Mascherano, have also been been accused of tax fraud, with the former ordered to stand trial.
Messi scored twice as Barcelona beat Eibar 4-2 at the weekend.
However, the result was not good enough to win the La Liga title ahead of Real Madrid.
Barcelona face Alaves in the Copa del Rey final this weekend.
Barcelona fans pay tribute to Lionel Messi after scoring 500 goals for the club