"Thunder" is a song recorded by English boy band East 17, released as the first single from their third album, Up All Night (1995), on 23 October 1995 by London Records. It was written by band member Tony Mortimer, who co-produced it with Ian Curnow, Phil Harding and Rob Kean. The song achieved success in many countries, including Belgium (Wallonia), Germany, Ireland, Norway, Switzerland and the UK, where it was a top-10 hit. Its music video was directed by Francis Ridley, featuring the band performing at an indoor set, where it later begins to rain.

Up All Night is the third studio album by East 17 and the last to feature the group's entire original lineup. It was released in November 1995. It is notable in that all members of the group made songwriting contributions to the album, although all three singles released were still penned solely by Tony Mortimer.