Romeo and Juliet starts out with a street fight between the Montagues and Capulets; the Jets and the Sharks have a similar fight.
The beginning fight is broken up by Krupke and Schrank, just as Prince Escalus breaks up the Montague-Capulet fight.
Tony has a recurring dream, like the one Romeo describes to Mercutio.
Juliet is betrothed to Paris, and Maria has been set up with Chino.
Some Montague men crash the Capulet party in which Romeo meets Juliet. In West Side Story, Maria and Tony see each other from opposite sides of the gym and are immediately attracted to each other.
Romeo searches for Juliet and finds her at her balcony. After the dance, Tony finds Maria and uses the fire escape.
Romeo and Juliet go to a Friar to get married; Maria and Tony role-play a wedding during their tryst in the bridal shop.
In the rumble scene, Bernardo kills Riff like Tybalt kills Mercutio; Tony avenges Riff's death by killing Bernardo, just as Romeo kills Tybalt.
The Capulet nurse is played around with and disgraced by Montague men, while Anita is taunted and attacked by the Jets.
Both stories feature Maria/Juliet's false death and Tony/Romeo's suicidal response to his mistaken belief that his love is dead. An enraged Anita, following the attempted rape, deliberately tells the Jets that Chino has killed Maria, instead of conveying the original message of where Tony should meet with her. Juliet fakes her death, but an explanatory message sent to Romeo is delayed, causing him not to know her death is but feigned. Tony seeks out Chino in misery, wishing to die also. Romeo wishes to visit Juliet's grave to take poison and die with her.