Continuity mistake: After Danny has knocked over a hurdle, we see him getting up; however, the Hurdle has either moved and stood itself back up or it's disappeared completely. In the next shot it has returned to its fallen position.
Continuity mistake: When Patti gets her skirt lifted up at the dance contest, the two boys who were dancing on either side of her in the previous shot have both disappeared.
Continuity mistake: When Danny and Cha-Cha are dancing to 'Born to Hand Jive', watch the position of Principal McGee. During the song, you can see her in the crowd. A few shots later, she is now standing near the stage on her own, and when we return to Danny and Cha-Cha dancing, you can see the Principal back in the crowd again.
Continuity mistake: On the first day of school during lunch, at one point Frenchie has out a small compact and is checking for food in her teeth. But when it cuts to a wider angle, suddenly the compact is gone, and she's looking over her shoulder.
Continuity mistake: At the start of the Rydell fight song at the dance, Patty is standing right at the front of the stage. One second later, she is at the back of the gym.
Continuity mistake: At the dance contest when principal McGee asks for applause for the committee who decorated the hall, someone replies "lets hear it for the toilet paper" and Eugene changes position during the following shots.
Continuity mistake: When the girls are all sitting in the outside cafeteria just before Patty Simcox comes over watch Marty. When Patty approaches she is lifting her fork to her mouth but when the shot changes she is holding out her hand to get Patty's card without having enough time to put her fork down in between.
Continuity mistake: At the dance-off, near the end of Cha-Cha and Danny's dance, they move from the back to the left side of the ring of people around them, and then in the next shot they're at the back of the ring.
Continuity mistake: There are red and white puffy paper decorations on each side of the door entering the gym for the dance-off. However, within a few seconds, the decorations on the left side completely disappear.
Continuity mistake: When the students are dancing to "Hound Dog" at the National Dance Off, they go up to the TV camera and start waving. You can see in the crowd a girl in a blue dress jumping up and down, but when we see it on the TV from the Frosty Palace, the girl is nowhere to be seen.
Audio problem: When Johnny Casino & the Gamblers perform "Hound Dog" at the National Dance Off, you can hear the song, but if you look carefully you can see it does not match the lead singer's lips.
Continuity mistake: When the waitress is cleaning off the table after the kids leave, the plates on her tray all appear to be empty. But Danny's and Sandy's plates are completely full when they leave, and no one touches their food. Kenickie takes one bite of a burger on a different plate, but not nearly enough to empty it.
Continuity mistake: When Rizzo is lying on the bench, and kicks off Sandy and that other chick, Sandy is singing, however her mouth is not moving at all.
Continuity mistake: In the lunch scene, when Rizzo and Marty first sit down, there is a half-eaten apple in front of Rizzo's lunch tray that keeps disappearing and reappearing between shots.
Continuity mistake: Sonny has a lunch bag in his hands when they arrive at school. After they see and talk with Zucco, the bell rings and they head for class. As they start leaving, Sonny doesn't have his lunch bag anymore.
Suggested correction: While the T-Birds are still outside you see Sonny putting his lunch in his coat pocket.
Continuity mistake: At the end of the prep rally, after Sandy confronts Danny, she is leaning on a car crying. Frenchie comes up to Sandy to console her. Watch Sandy's head, in one shot her head is up then in the next it is down.
Visible crew/equipment: When Danny is about to play basketball with the other students and Coach Calhoun is speaking to him, you can see the shadow of the boom mic behind the coach.
Continuity mistake: At the end of Principal McGee's final speech before the students' graduation carnival, the Principal gives Blanche a tissue and says, "Oh Blanche, stop blubbering". Blanche then puts the tissue over her nose, but in the next scene when she bursts into tears, the tissue has opened up and is covering the left side of her cheek.
Continuity mistake: During the dance off, Sandy and Danny are dancing in the center and everyone is watching them. Behind Sandy, Cha Cha walks out and puts her hands on her hips. Then, the camera does a close up of her doing this. So she actually walked out twice.
Continuity mistake: Rizzo is singing the Sandra-Dee song in Frenchie's bedroom. When she sits at the desk, you can just see that the chest of drawers are all closed fully behind her. However, later in the song Rizzo jumps off the bed. As she passes, then sits back at the desk, the second drawer down is now partially open. No one goes near it during this time, as all the girls in this song are on the bed.
