Tommy's rented limousine is a mid-1980's Chrysler K-car. When Julie and Randy make their escape from the Valley High prom, the limousine had changed into a Lincoln Town Car.
The clothes on the floor when Skip and Suzi are caught in bed together are not the same ones Skip was wearing when he entered the house.
Tommy's tuxedo trousers change from pink to black and back again at the prom.
In the party scene where Julie first meets Randy and Fred and the two guys are kicked out of the party we see Julie standing inside the house looking out the window. From the outside it shows her closing the shutters but when it switches back to Julie on the inside of the house, she hadn't closed them yet.
When the teacher is giving her speech before introducing the prom king and queen, she takes her glasses off and keeps them off for the rest of her speech. During the shots where Randy and Tommy are fighting, however, the teacher is shown in the background with her glasses on. The teacher's glasses are still off when the curtain pulls back to reveal Randy punching out Tommy, but right before she faints from the sight, her glasses are back on her face.
When the girls are dancing to "Girls Like Me" at Suzi's slumber party, the album spinning on the turntable clearly has an A&M Records label on it, but the album that contained that song at the time was actually released on Slash Records.
There is a myth that the opening scene supposedly takes place at the Sherman Oaks Galleria, but the sign on the door from which Julie and her friends leave the mall indicate that they are at the Del Amo Fashion Center, which is located in Torrance, California. However, there is no indication that they are at the Sherman Oaks Galleria, it's never mentioned and there are no signs that read Sherman Oaks Galleria.
When Julie and Tommy are at Du-par's, he puts his bracelet on her wrist, but because he does not properly fasten the clasp, one end of the bracelet clearly falls open on the table. Deborah Foreman has to obviously keep her wrist rigid on the table for the rest of the scene in order to keep the bracelet from slipping any further.
During the party scene, Suzi's mark is visible by her feet while she is dancing.
When Randy, Julie, Fred and Stacey enter the night club, The Plimsouls are performing their song Everywhere At Once. They are lip syncing to the recorded version which has keyboard parts but there is no keyboard player seen on stage.
During the party scene, the entrance to the bathroom is at the top of the stairs on the right. But when Skip sneaks into the bathroom while Suzi is showering, the entrance is through Beth's bedroom.
Despite the chauffeur understanding he was to drive to the "Valley Sheraton," The final visual in the movie is of the limo going away from the Valley, towards Century City, Marina del Rey and LAX on the 405 South.
The actress who plays Julie's mother appears much younger than Julie (Deborah Foreman).