Hot Rats is the second solo album and eighth overall album by Frank Zappa, released in October 1969. It was Zappa's first recording project after the dissolution of the original lineup of the Mothers of Invention. Five of the six songs are instrumental, while "Willie the Pimp" features vocals by Captain Beefheart. In his original sleeve notes, Zappa described the album as "a movie for your ears".

Zappa dedicated the album to his newborn son, Dweezil. In February 2009, Dweezil's tribute band to his father, Zappa Plays Zappa, won a Grammy for Best Rock Instrumental Performance for their rendition of "Peaches en Regalia".

Because Hot Rats largely consists of instrumental jazz-influenced compositions with extensive soloing, the music sounds very different from earlier Zappa albums, which featured satirical vocal performances with extensive use of musique concrète and editing. Besides Zappa, multi-instrumentalist Ian Underwood and guitarist Lowell George are the only members of the Mothers to appear on the album, with Underwood being Zappa's primary musical collaborator. Other featured musicians were bassists Max Bennett and Shuggie Otis (who was only 15 years old at the time of the session); drummers John Guerin, Paul Humphrey and Ron Selico; and electric violinists Don "Sugarcane" Harris and Jean-Luc Ponty.

This was the first Frank Zappa album recorded on 16-track equipment and one of the first albums to use this technology. Machines with 16 individual tracks allow for much more flexibility in multi-tracking and overdubbing than the professional 4 and 8-track reel-to-reel tape recorders that were standard in 1969.

In the Q & Mojo Classic Special Edition Pink Floyd & The Story of Prog Rock, the album was number 13 in its list of "40 Cosmic Rock Albums". It was also included in the book 1001 Albums You Must Hear Before You Die. In 2000 it was voted number 123 in Colin Larkin's All Time Top 1000 Albums.

The album was recorded on what Zappa described as a "homemade sixteen track" recorder; the machine was custom built by engineers at TTG Studios in Hollywood in late 1968. Additional tracks made it possible for Zappa to add multiple horn and keyboard overdubs. Only a few musicians were required to create an especially rich instrumental texture which gives the sound of a large group. It was this use of advanced overdubbing that was the main motivation for Zappa, who hated playing in a studio.

The colorful, psychedelic aura of the late sixties is apparent in the graphic design and photography of Hot Rats. This one-disc album had a gatefold featuring the elaborate artwork of Cal Schenkel, at a time when gatefold covers were less common and just coming into vogue. The front and back cover photos by Andee Nathanson use infrared photography and reflect Zappa's taste for striking visual images, combined with the absurdly humorous. The woman pictured on the cover is Christine Frka, alias Miss Christine of The GTOs. For years these cover photos were incorrectly credited to Ed Caraeff.

The LP was released on the blue Bizarre label in the United States in 1969. The inside of the original gatefold LP cover has a collage of color pictures, many of which were taken during the recording sessions. In 1973 the album was re-issued by Reprise Records. This version was deleted in 1981 when Zappa's contract with record distributor Warner Bros. Records ended.