| Professor Sir Paul Mellars FBA | Year of birth None | Year of death 2022 | Year elected 1990 | Fellowship category UK |
| Mr Paul Mellon Hon KBE, Hon FBA | Year of birth 1907 | Year of death 1999 | Year elected 1994 | Fellowship category Honorary |
| Excmo Don Ramón Menéndez Pidal FBA | Year of birth 1869 | Year of death 1968 | Year elected 1920 | Fellowship category Corresponding |
| Don Marcelino Menéndez Y Pelayo FBA | Year of birth 1856 | Year of death 1912 | Year elected 1909 | Fellowship category Corresponding |
| Professor Benjamin Dean Meritt FBA | Year of birth 1899 | Year of death 1989 | Year elected 1940 | Fellowship category Corresponding |
| Professor Reinhold Merkelbach FBA | Year of birth 1918 | Year of death 2006 | Year elected 1986 | Fellowship category Corresponding |
| Professor Robert Merton FBA | Year of birth 1910 | Year of death 2003 | Year elected 1994 | Fellowship category Corresponding |
| Revd Professor Bruce Metzger FBA | Year of birth 1914 | Year of death 2007 | Year elected 1978 | Fellowship category Corresponding |
| Revd John Meyendorff FBA | Year of birth 1926 | Year of death 1992 | Year elected 1977 | Fellowship category Corresponding |
| Professor Edward Meyer FBA | Year of birth 1855 | Year of death 1930 | Year elected 1910 | Fellowship category Corresponding |
| M Paul Meyer FBA | Year of birth 1840 | Year of death 1917 | Year elected 1904 | Fellowship category Corresponding |
| Professor Dr Kazimierz Michalowski FBA | Year of birth 1901 | Year of death 1981 | Year elected 1970 | Fellowship category Corresponding |
| Professor Georgi Mihailov FBA | Year of birth 1900 | Year of death 1991 | Year elected 1972 | Fellowship category Corresponding |
| Professor Sir Fergus Millar FBA | Year of birth 1935 | Year of death 2019 | Year elected 1976 | Fellowship category UK |
| Sir Oliver Millar GCVO, FBA | Year of birth 1923 | Year of death 2007 | Year elected 1970 | Fellowship category UK |
| Dr Edward Miller FBA | Year of birth 1915 | Year of death 2000 | Year elected 1981 | Fellowship category UK |