The Brazilian, who injured his ankle on February 19 against Lille in Ligue 1, "has had several episodes of instability in his right ankle in recent years," said the club, adding that its medical staff "recommended a ligament repair operation to avoid a major risk of recurrence".
Neymar tweeted he would not be discouraged by his latest injury. "I'll come back stronger," he wrote with a praying hands emoji.
Qatar-owned PSG said Neymar would go under the knife in Doha "in the next few days" and said it would take "three to four months before he can return to training with the team".
That would appear to end any prospect of Neymar playing again this season, with the Ligue 1 season due to end on June 3 and the Champions League final, if PSG were to get there, a week later in Istanbul.