Continuity mistake: When Harry and Sally are in the car driving to New York, in the front shots you see the car has no rear-view mirror.
Factual error: At one point, on the University of Chicago campus, the main characters drive through Cobb Gate, the ornate Gothic gate at the north end of the university quads. Cobb Gate is now and has been for many, many years, closed to motor traffic.
Continuity mistake: During the fake orgasm scene, the bite on Harry's sandwich increases and decreases between shots.
Continuity mistake: When the couple exit the first diner they get in the car and start to talk. The stuff on the back seat changes between angles.
Continuity mistake: When the movie starts, Harry is kissing a woman while Sally waits in the car. A couple passes behind the car, but they disappear in the close-up.
Continuity mistake: When Harry and Sally are on their way from Chicago to New York, Sally's hair changes. You have to really look for it, but watch the curl in front appear and then disappear.
Visible crew/equipment: On their way to New York, the couple stops at a Deli. When they open the car's door, film crew are reflected.
Continuity mistake: In the fake orgasm scene in the restaurant, when Meg Ryan holds her sandwich up there's one bite out of it, then it flicks on to Billy Crystal and when we see the sandwich again it has two bites out of it, but there was no time for her to have eaten any more. Later it has one bite again.
Continuity mistake: Throughout the movie, Meg Ryan's hair changes styles to depict the different eras. But in a montage of her and Billy Crystal, when it looks like she is doing yet another of her long winded menu requests to an exasperated waiter, he hair is straight and almost waist length. This is her hair style at the very end of the movie, when she and Billy are telling about their wedding cake with the coconut and rich chocolate sauce.
Continuity mistake: During the dinner scene in the restaurant, Marie puts down her glass of cola on the table. In the next shot, she is drinking from the glass again.
Continuity mistake: When Harry and Sally are walking to the museum, telling their stories about their sex dreams, Sally does not have a brooch anywhere on her blazer. However, when they are in the museum, she suddenly has a round brooch on the left lapel of her jacket.
Continuity mistake: When Sally is faking her orgasm, the slice of meat on her sandwich changes the way it's folded over the bun between angles.
Continuity mistake: In the first deli on the way to New York, Sally slides the menu over the table and places it aligned with the border, very close to her. When the angle changes, it is skewed and several inches away and she is bringing it close again.
