| Sir Thomas Arnold FBA | Year of birth 1864 | Year of death 1930 | Year elected 1926 | Fellowship category UK |
| Professor Geoffrey Arnott FBA | Year of birth 1930 | Year of death 2010 | Year elected 1999 | Fellowship category UK |
| Professor Raymond Aron FBA | Year of birth 1905 | Year of death 1983 | Year elected 1970 | Fellowship category Corresponding |
| Professor Kenneth Arrow FBA | Year of birth 1921 | Year of death 2017 | Year elected 1976 | Fellowship category Corresponding |
| Professor Michael Artis FBA | Year of birth 1938 | Year of death 2016 | Year elected 1988 | Fellowship category UK Emeritus |
| Dr Thomas Ashby FBA | Year of birth 1874 | Year of death 1931 | Year elected 1927 | Fellowship category UK |
| Professor Bernard Ashmole CBE, FBA | Year of birth 1894 | Year of death 1988 | Year elected 1938 | Fellowship category UK |
| Professor Thomas Ashton FBA | Year of birth 1889 | Year of death 1968 | Year elected 1951 | Fellowship category UK |
| Dr Margaret Aston CBE, FBA | Year of birth 1932 | Year of death 2014 | Year elected 1994 | Fellowship category UK |
| Professor Patrick Atiyah QC, FBA | Year of birth 1931 | Year of death 2018 | Year elected 1978 | Fellowship category UK Emeritus |
| Rt Hon Lord James Atkin of Aberdovey PC, FBA | Year of birth 1867 | Year of death 1944 | Year elected 1938 | Fellowship category UK |
| Professor Sir Tony Atkinson FBA | Year of birth 1944 | Year of death 2017 | Year elected 1984 | Fellowship category UK |
| Professor Roger Aubert FBA | Year of birth 1914 | Year of death 2009 | Year elected 1980 | Fellowship category Corresponding |
| Revd Michel Aubineau FBA | Year of birth 1921 | Year of death 2002 | Year elected 1986 | Fellowship category Corresponding |
| Dr Gustaf Emmanuel Hildebrand Aulén FBA | Year of birth 1879 | Year of death 1977 | Year elected 1971 | Fellowship category Corresponding |
| Professor Colin Austin FBA | Year of birth 1941 | Year of death 2010 | Year elected 1983 | Fellowship category UK |