01011001 is the seventh studio album by Arjen Anthony Lucassen's long-running Ayreon project. "01011001" is the binary representation of the ASCII value of the letter Y.

01011001 is a concept album that tells the story of aliens called the "Forever", who create humanity, only to later endanger it by providing it with technology.

Seventeen singers in total, including Lucassen himself, contributed to the album, more than any other Ayreon album. Apart from Lucassen, only Anneke van Giersbergen (ex-The Gathering) and Floor Jansen (After Forever, Nightwish) had sung on previous Ayreon albums, on Into the Electric Castle and Universal Migrator Part 1: The Dream Sequencer respectively.

It also stars, among others, Bob Catley from Magnum, Hansi Kürsch from Blind Guardian, Jørn Lande, and Steve Lee from Gotthard in his final guest appearance before his death in 2010. The album was a commercial and critical success.