Longtime NBA referee Eric Lewis is retiring ... just a couple months after the league announced it was looking into allegations he wrongfully used social media.
The 19-year-vet, who's officiated over 1,200 regular-season and playoff games, informed the league of his decision on Wednesday ... according to NBA officials.
The league added its probe into Lewis' alleged social media activity is now closed.
As we previously reported, the NBA initially began its investigation back in the spring ... after some claimed now-deleted tweets regarding the league's officiating came from a burner account belonging to the 52-year-old.
The NBA, of course, does not allow refs to publicly comment on officiating ... and while they looked into the matter, they pulled Lewis from his role as an NBA Finals ref.
At the time, Adam Silver said he didn't think it would be "appropriate for him to work" the games amid the allegations.
It's still not yet clear if the account did, in fact, belong to Lewis.