John Harold Westgarth Voelcker (1927-1972) was a British architect and designer. He was the first Professor of Architecture at the University of Glasgow.
Voelcker was born in Preston, Lancashire. He studied at the Architectural Association (AA) and then worked in Milan, later returning to London, where he became a member of the Royal Institute of British Architects.
In the early 1950s Voelcker was a member of Team 10, dominated by Peter and Alison Smithson, but later split with the group. In 1954 he moved to Kent where he developed a country practice creating designs for farm improvements, school and office buildings. He also worked on houses and housing schemes for local authorities and businesses. At the same time he taught in various capacities concerning planning and public design, including work at the AA School and Cambridge University.
In 1958 a dispute with local planning authorities over a building designed for the Jazz musician Humphrey Lyttelton led to Voelcker and Lyttelton successfully challenging the authorities. The building was a dramatic U-shaped structure and included a "splendidly witty" pop art mural by McHale. As a result of their defence of creative architecture Voelcker and Lyttelton were named the Architect's Journal's men of the year.