Greta Celeste Gerwig is an American actress, writer, and director. Initially known for working on mumblecore films, she has since expanded from acting in and co-writing independent films to directing major studio films. Gerwig was included in the annual Time 100 list of the most influential people in the world in 2018.

Mumblecore is a subgenre of independent film characterized by naturalistic acting and dialogue, low budgets, an emphasis on dialogue over plot, and a focus on the personal relationships of young adults. Filmmakers associated with the genre include Andrew Bujalski, Lynn Shelton, the Duplass brothers Mark and Jay, Greta Gerwig, Aaron Katz, Joe Swanberg, and Ry Russo-Young. In many cases, though, these directors reject the term. The genre is a mostly American phenomenon. The related term mumblegore has been used for films mixing the mumblecore and horror genres.