Audio problem: During the opening overture, right when the orchestra starts "Maria", you can hear someone sneeze in the background. It's easier to hear on the soundtrack but you still can hear it in the movie.
Other mistake: During "Cool," there's a shot where they're doing a sort of knee turn, and you can see Tucker Smith in the background spinning too many times (you can see him start to stick out his arms to stop himself).
Continuity mistake: In the prologue, when the Jets are talking about Tony, Ice goes, "Man, remember them fists the day we clobbered the Emeralds." you can see A-Rab with his arms crossed. In the next shot they're uncrossed and he crosses them.
Other mistake: When Nardo is piercing John's ear, it's obviously just him and the Sharks, but then in the shot from above, you can see all the Jets running to the rescue. Also, Ice is already there, throwing a Shark off of John.
Continuity mistake: Near the end of the movie, when Maria (Natalie Wood) is kneeling over Tony's (Richard Beymer) dead body, watch the cross around her neck. first it's sort of tucked into the top of her dress, then it is on the outside. it goes back and forth several times.
Continuity mistake: During the rumble, Riff slashes at Nardo's shirt with his knife and he spins away, but you can't see any tear in his shirt. Then in the next shot, when Riff is running toward him again there's a noticeable cut in his shirt (on the back).
Continuity mistake: At the gym during the dance, Baby John tells Riff, "Pick up" when Nardo and the Sharks come into the gym, and all the Jets stop dancing - except for Ice and Velma. Then in the next shot, Ice is suddenly in the big Jet mob, and Velma is off to the side with Graziella.
Continuity mistake: Toward the end of the movie when Doc slaps Tony, Tony grabs his face. Then they show a behind shot of Tony and you can see his hand moving slowly away from his face. But when they show a front shot of Tony his hand is back on his face.
Continuity mistake: During the scene when the Jets and the Sharks are chasing each other around, when the jets are in shark territory, 4 boys get splashed with yellow paint. When all the boys are back on the playground nobody is covered in yellow paint.
Revealing mistake: In the final scene, if you look in the background that is completely opposite of the gate where the characters exit, there are two cars obviously made of cardboard. Many times they can be seen by looking over Maria's shoulder.