Sir Evan Owen Williams was a British engineer and architect, known for being the principal engineer for Gravelly Hill Interchange (known popularly as Spaghetti Junction) as well as a number of key modernist buildings, including the Express Building in Manchester and Boots D10 Building in Nottingham.

Primarily an engineer, he was not classically trained as an architect but showed an exceptional degree of proficiency with both flair and functionality in his buildings which were considered far ahead of their time during the 1930s. Williams ultimately believed architecture and engineering must be inseparable.

In 1912 Williams assumed a position as engineer and designer with the Trussed Concrete Company.Seven years later, he started his own consulting firm, Williams Concrete Structures. Williams designed his buildings as functional structures sheathed with decorative facades.

In the 1940s the company expanded and became Sir Owen Williams and Partners. This followed the building of the Daily Express Building, Manchester which Williams designed. Contrary to popular belief, the Manchester building was the only one of the three Express Buildings which Williams designed - the others in Glasgow and London were designed by Ellis and Clark. Although Williams was more of an engineer than an architect, the Manchester Express Building was lauded for architecture and demonstrated his proficiency as an architect.