Star One (also referred to as Arjen Anthony Lucassen's Star One) is a Dutch progressive metal supergroup/side-project of Arjen Anthony Lucassen of Ayreon fame.

The band has released three albums to date: their first in 2002, their second in 2010, and most recently a third in 2022, plus a live album in 2003, and features four different singers: Russell Allen (Symphony X), Damian Wilson (Threshold, Headspace, Arena), Dan Swanö (Edge of Sanity, Nightingale), and Floor Jansen (After Forever, ReVamp, Nightwish).

Unlike Ayreon, albums do not follow one storyline; instead, each song is a different story with a sci-fi concept, most of the tracks based on existing movies and series. The band takes its name from the second season finale of Blake's 7. The band includes four singers alternating in all the songs, not including Lucassen, who sings occasionally, plays all guitars and keyboards and writes and composes all the songs. The third studio album deviates from this, having a different guest singer on each track.