In a World... is a 2013 American comedy film written, directed, starring, and co-produced by Lake Bell. The film stars Bell as a vocal coach who does voice-overs for film trailers. The film co-stars Demetri Martin, Fred Melamed, Rob Corddry, Michaela Watkins, Ken Marino, Nick Offerman, and Tig Notaro.

The film debuted at 2013 Sundance Film Festival in January and had its international debut at Sundance London in April before an August 2013 theatrical release. The film grossed $3.1 million against a production budget of less than $1 million. Most of the gross was domestic. Bell presents the subject matter as a lifelong interest and a natural pursuit based on her life experiences; she spent several years writing the film's script.

The film received positive reviews from critics and accolades from institutions such as the Sundance Film Festival and the National Board of Review.