Factual error: When Andy is in the club with his future manager in the audience, he tells the crowd (in his Foreign Man persona) that he is going to imitate President Carter. After hooking up with his manager, he gets a gig on the first episode of Saturday Night Live, which debuted in 1975. Jimmy Carter wasn't President until 1976.
Factual error: In the film, Andy plans the Carnegie Hall gig after learning he has cancer. The actual concert took place in 1979, when Kaufman's popularity was at its highest, not near the end of his life and career (1983-84). (Regardless of the writers' intent when writing the script for this film, it is still a factual error.)
Factual error: In the scene that depicts the infamous Andy Kaufman vs. Jerry Lawler match, the movie has Jim Ross as the play-by-play man for the match. In the actual match it was the ring announcer in the movie, Lance Russell, who was the original play-by-play man, not Jim Ross.
Factual error: Andy didn't meet his girlfriend Lynn when he was wrestling women on the Merv Griffin show. They actually met in 1981-82, when his "wrestling career" was dying down (incidentally, if you rent the movie "My Breakfast With Blassie", you actually see Andy meeting, and hitting on, Lynn for the first time. They had never met prior to the filming of their improvised scene. It's pretty funny-rent it!)
Factual error: At Andy's funeral Jerry Lawler's real life wife Stacey "The Kat" Carter can be seen sitting next to him, but the only problem is Andy supposedly died in 1984, and Jerry Lawler's wife would've only been 14 at the time. I don't even think that they met till a couple of years later, yet she's still there and looks to be about 29 or 30 - her current age.