Lightbulb Sun is the sixth studio album by British progressive rock band Porcupine Tree, first released in May 2000, and later reissued in 2008 on CD, DVD-A surround sound, and vinyl.

Porcupine Tree are an English rock band formed by musician Steven Wilson in 1987. During an initial career spanning more than twenty years, they earned critical acclaim from critics and fellow musicians, developed a cult following, and became an influence for new artists. The group carved out a career at a certain distance away from mainstream music, being described by publications such as Classic Rock and PopMatters as "the most important band you'd never heard of".