Gillian Margaret "Jill" Howell (née Sarson, 1927–2000), was a British architect.

She was born Gillian Margaret Sarson, on 3 November 1927 in Multan, in the western Punjab, British India, the daughter of Colonel Edward Vipan Sarson, commandant of the Royal Artillery training centre, and his Norwegian wife, Dagny Sarson.^[1] She was educated at the Royal School, Bath, followed by the Architectural Association School of Architecture in London.^[1]

As Gill Sarsen, together with her future husband, Bill Howell, and Stanley Amis, they designed a modernist terrace of six houses at Nos. 80-90 South Hill Park, on the south side of Hampstead Heath, to replace four Victorian houses lost to World War Two bombing.^[2] All three were employed by the London County Council's Architect's Department Housing Division, and they ended up living in two of the six houses.^[2] Their designs were highly influential and much publicised, and led to them working on the Alton Estate tower blocks in Roehampton.^[2] The terrace is now Grade II listed.^[2][3][4]

She later founded her own architectural practice with Jean Elrington.^[1] After her husband's early death, she continued teaching at the University of Cambridge school of architecture, and took over her husband's role as a governor of Marlborough College and advisor on its buildings.^[1]

She met her future husband, fellow architect Bill Howell on an Architectural Association School outing to the Bryn Mawr rubber factory in Wales.^[1] They married on 10 August 1951, and had three sons and one daughter.^[1] He died on 29 November 1974 in a car accident near Leighton Buzzard, Bedfordshire, aged 52.^[1]

In 1995, she married Mike Watt, a retired company secretary.^[1]

On 2 May 2000, she died at her home, Fen Ditton Hall, Fen Ditton, Cambridge, from cancer, and was survived by her second husband.^[1]