Goofs

During the luau, after the twins fall into the pool with Balmudo, they reappear in the crowd behind the T-Birds when Michael gets his jacket, obviously dry.

During the luau people appear and disappear on the boat.

Johnny and Stephanie are trying to paddle the raft when Michael shows up. A few seconds later he jumps the pool on his motorcycle and we can see that now Johnny and Stephanie aren't moving at all, and the water is suddenly completely still. On top of that, a second later one of the motorcycle gang jumps his bike into the pool and it's once again calm. Then his buddy also tries to jump the pool right after him and the water is still somehow flat as a pancake when he hits it.

At the end during the luau, when the bikers are falling into the pool, Stephanie and Johnny are getting out of the unseen side of the pool, but after Michael takes off his helmet, Stephanie is just barely getting out and Johnny is still on the boat.

When Johnny tilts the pinball machine he's playing at the Bowl-a-Rama, the machine shuts down and the back glass display goes dark. Goose straightens out the machine, but it remains off. In the next shot from a different angle, the machine can briefly be seen in the background with a lit up back glass although there was no time for the management to manually reset it.

Michael isn't mentioned after he disappears before the talent show, but he's shown at the luau twice before Balmudo and company appear, eating cotton candy in front of the pool during the day.

The year for the June Moon Talent Show should've been 1962 for the year that this senior class that started in Sept. (?) 1961 graduated in.

Everybody is dancing at the bowling alley and even dancing on the alleys. The alleys in a bowling alley are heavily waxed so the bowling balls don't have friction while rolling. Everyone dancing on the alleys would be slipping, sliding and falling all over the place.

During the song "Score Tonight" the characters are seen dancing/sliding down the lanes. Actually if you do that at a real bowling alley, you will slip and injure yourself.

In the beginning of the "were going prowling" scene you can see DiMucci's pants are a dark Grey color. Later on they are a light blue color.

Both times the two motorcycles jump the pool, the luau raft is missing in the pool underneath.

At the talent show, Stephanie is covered in fake snow when she begins singing. The snow disappears then reappears at the end of the song.

At the end, when a bike flips into the pool, the cord used to make the bike flip is visible.

When Michael and Frenchie are walking past the yellow school buses in the beginning, a male backing dancer twirls straight into a post, smacking his shoulder.

At the luau, just before Balmudo's motorcycle gang crashes through the tiki hut and table, a blonde woman in a dress, a man in a red-and-white Hawaiian shirt, and a man in white shorts can be seen standing on the right side of the scene staring at the tiki hut waiting for their cue to turn and run when the bikers show up "unexpectedly".

When Stephanie gets on the mystery riders motorcycle , she puts her feet on the tail pipes , this would definitely have ruined the bottoms of her shoes .

At the graduation scene at the end, when all the students remove their caps and go to throw them in the air, Stephanie clearly drops hers.

In the scene near the beginning of the movie where the twins interrupt Michael while he is running around the track, a guy is on his left jumping hurdles. After he jumps the second one, his goods fall out of his shorts. He discreetly tries to cover himself for the rest of his time in the scene.

After "Reproduction", cuts to Michael finishing essay for Davey J. It's title reads "Sex Morality & the Animall Kingdom", with the word animal clearly misspelled.

Outside the diner, when Johnny tells Stephanie to return her T-Bird jacket, she walks off and passes a 1980s Peterbilt semi tractor-trailer.

When Michael is walking in the parking lot to the bowling alley, a modern gas station is visible behind him. Black curtains are visible behind the cars, apparently to hide the gas station.

At least two of the pinball machines at Bowl-a-Rama weren't made until the early 1970s.

This film is set in 1961, yet a modern skateboard appears. Boards of this type were not generally available until the early 1970s.

Many of the female dancers obviously wear pantyhose, as do Paulette and others in the talent show. Pantyhose and tights weren't commonly available until later in the 1960s.

In a close-up toward the end of "Score Tonight", Johnny is singing the wrong lyrics when he looks ahead; Paulette does the same in the previous scene.

This is not an actor error. Everyone here is mouthing "score", but the soundtrack says "tonight".

The same happens in the previous scene when Paulette and all are saying "tonight", but you hear "score". This is definitely an editing error, not an actor error.

In 'Score Tonight', near the beginning of the song, there's a close-up of the Pink Ladies and Sharon forgets the words.

During the talent show Principal McGee calls the T-Birds "the T-Bones" and Johnny corrects her but no sound is heard, although his lips form the words.

When Michael jumps the police at the Bowl-A-Rama, you can just see the ramp through the police car windows.

During the "Calendar Girl" sequence, as the fake snow falls, "January" (right side of screen, in a champagne glass) gets some in her mouth, and tries to spit it out instead of singing.

Eddie Deezen returns as Eugene. However, in the first movie, set two years earlier, he was portrayed as being a senior, and here he's still portrayed as a high school student.

After their romantic motorcycle ride, Stephanie asks Michael (still disguised as Cool Rider) when she'll see him again, to which he replies Friday night at the talent show before riding off. Stephanie then wonders how he knew about the talent show. In reality, a high school talent show, being a public event, would have been known by many people in and out of the school.

During the "Back to School" number, when Coach Calhoun is throwing a basketball at a kid, at the end of the scene Sid Caesar looks straight into the camera, which should have been edited out.