18 people died in the year 1921

• Emily Davies (1830 – 1921), founder of Girton College, Cambridge, pioneer of Women's education, campaigner for women’s education, and campaigner for votes for women
• William Davies (1831 – 1921)
• William Thomas Du Boulay (1832 – 1921), cleric
• Robert Awde (1838 – 1921), health inspector and chief health inspector for the City of Toronto
• Austin Dobson (1840 – 1921), poet and essayist
• Marcus Stone (1840 – 1921), artist
• John Boyd Dunlop (1840 – 1921), veterinary surgeon
• Henry Mayers Hyndman (1842 – 1921), socialist leader
• Peter Kropotkin (1842 – 1921), theorist of anarchism and Prince
• William Cecil Marshall (1849 – 1921), architect and first Wimbledon tennis finalist
• Franz Hitze (1851 – 1921), social politician
• Edward Lisle (1852 – 1921), founder of STAR Cycles, Cars and Commercial Vehicles
• Engelbert Humperdinck (1854 – 1921), composer
• William Friese-Greene (1855 – 1921), cinematograph pioneer, inventor of cinematography, inventor of the moving picture camera, inventor of commercial kinematography, and father of film
• William Strang (1859 – 1921), painter and etcher
• H. T. Hare (1860 – 1921), FRIBA, architect, and President of the RIBA (1917-1919)
• Wilhelm Ealdeyer (1886 – 1921), anatomist
• James Seaward (died 1921)