Cheer Up! is the fourth studio album by American rock band Reel Big Fish. Released on June 25, 2002, the album was the band's first after the turn of the new millennium, following the release of 1998's Why Do They Rock So Hard? With the advent of the 2000s, and following the band's mainstream success during the third wave of ska, the marketability of and interest in ska waned; despite this, Reel Big Fish continued to tour successfully and maintain a significant fan base while recording Cheer Up! across a number of different recording studios in California. Val Garay produced the majority of the tracks, with frontman Aaron Barrett, trumpeter Scott Klopfenstein and Gordie Johnson producing select songs.

Reel Big Fish is an American ska punk band from Huntington Beach, California. The band gained mainstream recognition in the mid-to-late 1990s during the third wave of ska with the release of the gold-certified album Turn the Radio Off. Soon after, the band lost mainstream recognition but gained an underground cult following. As of 2006, the band was no longer signed to a major record label and has since been independent. After numerous line-up changes, frontman Aaron Barrett is the last remaining founding member still performing in the band.