Lady Helen Cynthia Colville, née Milnes, later Crewe-Milnes, DCVO DBE JP FRCM (20 May 1884 – 15 June 1968) was an English courtier and social worker, serving as a Woman of the Bedchamber to Queen Mary, while at the same time devoting her energies to alleviating the suffering of Shoreditch, one of the poorest areas of the East End of London.

She started her work in Shoreditch, which was a slum (a "socially derelict square mile", as her son described the area), before World War I, focusing on infant mortality. The Socialist borough council co-opted her to their public health committee. In February 1952 while serving as Woman of the Bedchamber to Queen Mary it fell to Lady Cynthia Colville to inform Queen Mary of the death of her son George VI