Richard Beymer and Natalie Wood barely talked to each other in real life. They would say "Good Morning" to each other as if they'd just met, and then start making out when someone said "action." Whenever they finished a scene, Wood would go straight back to her trailer. She wasn't this cold toward many of the other actors in the film. Her ability to cover this up shows her great acting skills. This fact is also mentioned in the West Side Story Special Edition DVD.

In the original stage version Tony and Maria sing "One Hand, One Heart" on the fire escape on the night of the dance. This song was considered too solemn in that scene when the movie was made, so they lifted a tune from "Quintet" and did some lyrics adjustments. The result was "Tonight", which is still the song sung in that particular scene in most stage productions.

Tucker Smith (Ice) dubbed Riff's voice in the "Jet Song."

The bracelet Natalie Wood wears on her left wrist is to hide an injury she got while working on a previous movie.

The actors loved being on location in New York, so in order to get to stay there longer they would do rain dances to make it rain and delay production. It ended up raining so often that the director forbid them to do any more rain dances.

Rita Moreno was reduced to tears when she was nearly raped by the Jets(although it was only acting) when it brought back memories of her being raped as a child. When she started crying the cast immediatly stopped and tried to comfort her.

Eliot Feld had pneumonia when they were filming "Cool."The studio they were filming in was extremely hot so when the cast took a break they went outside in the cold air. This all took a toll on Eliot and he collapsed.

A lot of people know that Marni Nixon dubbed Natalie Wood's singing. But in fact, she also dubbed two of Wood's sentences - "Don't you touch him" and "Te adoro, Anton" in the end of the movie.

The songs "Cool" and "Gee, Officer Krupke" were switched around in the film version as the latter song felt too merry after Riff had just died. In most stage productions since the film's release the songs have appeared in the order they did in the film.