Will (William) Allen Alsop, OBE RA (born 12 December 1947) is a British architect based in London. He is responsible for several distinctive and controversial modernist buildings, most in the United Kingdom. Alsop's buildings are usually distinguished by their use of bright colour and unusual forms. While Alsop has won praise from some critics and fans of avant-garde architecture, he has also faced criticism from fellow architects and some segments of the general public.

Alsop hails from Northampton, Northamptonshire, England, he was born on 12 December 1947. He always wanted to be an architect, even before he really knew what architects did; when he was six years old, he designed a house for his mother to live in – its most striking specification was that it had to be built in New Zealand. When he was 16 his father, an accountant, died, and being bored with school he left to work for an architect, doing his A-levels at evening classes.

He was greatly influenced by his drawing tuitor, Henry Bird while at foundation course at Northampton Art School. He recalled how was taught to draw by him. "He gave me a brick, told me to draw it and promptly left the room. I proceeded to draw it with all its shadows. On his return he went into a rage and chastised me for destroying the vision with shading, shouting: 'What is wrong with a simple line?' He insisted that I redo the drawing with line only so that I could begin to see the brick and its proportions. I drew that brick for two three hour sessions per week, line only, for three months. Eventually, he admitted that I had mastered the brick and I was allowed to progress onto the tin can. After 18 months it was the nude model. His vision was one of economy of line and discipline. It worked."