Andy Tillison (born 21 June 1959) is a British keyboardist and singer best known for his work in the progressive rock bands Parallel or 90 Degrees and The Tangent.
One piece by this line-up, "A Gap in the Night", was later included on Parallel or 90 Degrees' The Corner of My Room, followed by the archival release No More Travelling Chess.
With Manning temporarily unavailable, Tillison and Baine recorded The Corner of My Room, subsequently released as the band's second album.
A new line-up of Parallel or 90 Degrees signed with Cyclops Records with Tillison, Baine, Lee Duncan (drums), Jonathan Barrett (bass) and Graham Young (guitar).
The line-up included Roine Stolt, Jonas Reingold and Zoltan Csorsz from The Flower Kings, David Jackson from Van der Graaf Generator and Guy Manning.