In 1995, she wrote and directed Clueless, reworking and updating Jane Austen's Emma as a 1990s teen comedy about wealthy teenagers living in Beverly Hills. Heckerling originally thought of Clueless as a television show because she loved to write the character of Cher who she described as a "happy, optimistic, California girl", and wanted to explore all of her adventures, but after she pitched it to her agent she was told that it would make a great feature. To research for the script, Heckerling sat in on classes at Beverly Hills High School where she observed how teenagers acted, though she admits that most of it was made up. She notes that teenagers at the high school did not dress in high fashion every day as the characters do in the film and that in reality the students there dressed just as frumpily as everyone else. She did, however draw on many of her observations, especially the tendency of teenage girls to groom themselves constantly. "You would think that within, you know, the few minutes that they've been in class, that their makeup wouldn't be needing so much repair and yet they're constantly painting and sculpting and ... doing to themselves." As with Fast Times at Ridgemont High, it quickly caught on with teenagers and went on to become a significant pop culture reference point. The film went on to gross $56,631,572 and helped launch the careers of most of the cast, including Alicia Silverstone, Brittany Murphy, Paul Rudd, Donald Faison, Breckin Meyer, and Stacey Dash. It was spun off into a moderately successful TV series, with Heckerling penning the pilot, as well as directing several episodes from the first season. Heckerling describes the show as basically the same as the film, only cleaner, and says that she still loves the characters.
In 1995, Heckerling won the National Society of Film Critics Best Screenplay award and was nominated for the Writers Guild of America award for Best Screenplay Written Directly for the Screen for her screenplay, Clueless. In 1998, she received the Franklin J. Schaffner Medal from the American Film Institute. In 1999, she received the Women in Film Crystal Award for outstanding women who, through endurance and excellence, have helped to expand the role of women within the entertainment industry.