“4 Walls” is a song recorded by South Korean-based girl group f(x) for their fourth studio album of the same title. The track was written by Jam Factory member Lee Seu-ran, whilst production was handled by LDN Noise, Tay Jasper, and Adrian McKinnon. Lee Soo-man, the former president at S.M. Entertainment, served as the executive producer to the track.
It was released on October 27, 2015 as the lead single in conjunction with the release of the album. Musically, “4 Walls” is described as a hybrid of tropical house, UK garage, and deep house.