Adult Swim (stylized as [adult swim]) is an American adult-oriented nighttime programming block of the children's basic cable network Cartoon Network. It is programmed by its in-house production studio, Williams Street. It currently broadcasts nightly from 8 p.m. to 6 a.m. ET/PT. The block is marketed as a separate network from Cartoon Network for ratings purposes, similar to Nick at Nite, the nighttime branding of Nickelodeon.

Debuting in 2001, Adult Swim serves as the nighttime identity of Cartoon Network, and was established as alternative programming during the late night hours when Cartoon Network's primary target audience, children between the ages of 7 and 15, would normally be sleeping. In 2005, the block was granted its own Nielsen ratings report from Cartoon Network due to targeting a separate demographic. The block features stylistically varied animated and live-action shows; including original programming, syndicated series, anime, original video animation, and short films with generally minimal or no editing for content. The block has frequently aired adult animation features, mockumentaries, sketch comedy, and pilots. The block's shows are known for their sexual themes, frank sexual discussion, nudity, strong language, and graphic violence. Many of its programs are aesthetically experimental, transgressive, improvised, and surrealist in nature. This has become a source of conflict, with some saying that Adult Swim is too controversial, while others noting that its ability to question the norm brings a level of surrealism and experimentalism that is welcome. Adult Swim has contracted with various studios known for their productions in absurd and shock comedy