Heathers is a 1988 American teen black comedy film written by Daniel Waters and directed by Michael Lehmann, in both of their respective film debuts.
The film stars Winona Ryder, Christian Slater, Shannen Doherty, Lisanne Falk, Kim Walker, and Penelope Milford. Its plot portrays four teenage girls—three of whom are named Heather—in a clique at a Sherwood, Ohio high school.
I would have sworn this was posted before but it seems not.
Fun tidbit from the wikipedia page: