The Outsiders (1983)

It is 1961, and Tulsa, Oklahoma is divided in two along social lines. The youths of each side form gangs in line with these two camps: the working class Greasers and the wealthier South Side gang, the Socs. The two sides use any opportunity to niggle each other and whenever they meet, there is friction.

Then one night, a gang of Socs attack two Greasers with a knife. This sets off a chain of events.