Gilbert O'Sullivan (born Raymond Edward O'Sullivan, 1 December 1946) is an Irish singer-songwriter, best known for his early 1970s hits "Alone Again (Naturally)", "Clair" and "Get Down". The music magazine Record Mirror voted him the No. 1 UK male singer of 1972.

Worldwide he has charted 16 top 40 records including six number one songs, the first of which was 1970's "Nothing Rhymed" (for further information see Gilbert O'Sullivan discography). Such was his popularity in the early 1970s that "Matrimony", an airplay and live favourite from his debut album Himself, remains one of his most famous compositions despite never having been a hit single.