Catherine Hiller (born November 16, 1946) is an American author and filmmaker, best known for writing Just Say Yes: A Marijuana Memoir. The first memoir about long-term cannabis use designed for a mainstream audience, Just Say Yes attracted national attention, being featured in The New York Times, Huffington Post, and Marie Claire magazine among other media outlets. In 2015, Hiller publicly "came out" as a cannabis user, saying that she has smoked marijuana almost every day for fifty years.