Geoffrey Charles Whitehorn (born 29 August 1951) is a guitarist and singer-songwriter, who has played as a member of If, Crawler and Procol Harum.

In August 1973, Whitehorn joined the pioneering British jazz-rock band, If, in what was their third and final line-up, appearing on their last two albums, Not Just Another Bunch of Pretty Faces (1974) and Tea Break Over, Back on Your 'Eads (1975).

During that period, he recorded his first solo album, Whitehorn (1974, Stateside), featuring fellow If members Dick Morrissey and Cliff Davies.

Geoff also played as lead guitarist with Chuck Farley besides Steve Simpson, Boz Burrell, Poli Palmer and Alan Coulter.

In 1991, he joined the group Procol Harum,[1] and was their second longest serving member (after founder Gary Brooker), having played on all of their recent recordings, such as The Long Goodbye, One More Time - Live in Utrecht 1992, The Well's on Fire and Novum as well as on Procol Harum's live DVDs in Denmark and at Union Chapel (Concert on Friday 12 December 2003), and one recorded with an orchestra in 2006 at Ledreborg Castle, again in Denmark.