Slippery When Ill is the second album by the Huntington Beachpunk rock band The Vandals, released jointly in 1989 by Restless Records and Sticky Fingers Records. It was their first album to include Dave Quackenbush on vocals, who would remain the band's singer for the rest of their career. The album was something of a departure from the punk rock formula of their previous releases, fusing a country and western style with their humorous brand of punk. The result was a sound the band called "cow punk" which somewhat mocked the resurgence in popularity of country music in their native Huntington Beach. Two exceptions were the songs "Shi'ite Punk" and "(Illa Zilla) Lady Killa," which relied heavily on scratch boxes. The latter song was a re-recording of the song "Ladykiller" from the band's previous album When in Rome Do as the Vandals with slightly altered lyrics.
Robbie Allen is credited in the album's liner notes as having performed all of the bass tracks on the album, but by the time of its release original member Joe Escalante had moved from Drums into the bass position. Escalante had played drums on the album, but when he switched to bass Doug Mackinnon joined the band as their new drummer. The photo in the album's liner notes indicates Escalante as the band's bass player and MacKinnon as their drummer.