Best friends since childhood and roommates since high school graduation, party girls Romy (Mira Sorvino) and Michele (Lisa Kudrow) are two carefree young women living in Southern California. When they hear about their upcoming ten-year high school reunion, the pair take stock of their lives since high school and are genuinely surprised to find they have very little to brag about. To compensate for their apparent lack of achievements, they decide to reinvent themselves, concocting fantasies of wealth and success to impress their former classmates.

Romy and Michele arrive at their high school reunion fully prepared to fake their way to acceptance especially when it comes to their old rivals, the snobby cheerleader clique. But their well-rehearsed charade takes an unexpected turn when former classmate Heather Mooney (Janeane Garofalo ) shows up and knows their real stories.