Up in Smoke (also referred to as Cheech & Chong's Up in Smoke) is a 1978 American buddy stoner comedy film directed by Lou Adler and starring Cheech Marin, Tommy Chong, Tom Skerritt, Edie Adams, Strother Martin, and Stacy Keach. It is Cheech & Chong's first feature-length film.

Cheech & Chong had been a counterculture comedy team for about ten years before they started reworking some of their material for their first film. Most of the film was shot in Los Angeles, California, including scenes set in Tijuana, while scenes set on the Mexican border were actually filmed at the border in Yuma, Arizona.

While negatively received upon its release, Up in Smoke grossed over $104 million, is credited with establishing the stoner film genre, and is now considered a cult classic. In 2024, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".