Websites like the Heathers Wiki or Musical Heaven sometimes transcribe individual scenes. These are not full scripts, but you can find:
"Heathers: The Musical" is a dark comedy that has gained a significant following for its sharp wit, catchy music, and exploration of complex themes such as bullying, social hierarchy, and teenage angst. The musical, which originated from the 1988 film of the same name, features a book and lyrics by Winnie Holzman and music and lyrics by Matthew Bright and Benj Pasek. heathers the musical script pdf
If you're planning to stage or read the script, consider the following: Websites like the Heathers Wiki or Musical Heaven