A
- William Adam (1909–1988) from Belgium
- Johann Christian Albers (1795–1857) from Germany
- Joshua Alder (1792–1867) from Great Britain
- Frederick Aldrich (1927–1991) from the USA
- Truman Heminway Aldrich (1848–1932) from the USA, civil engineer and paleontologist
- R. Tucker Abbott (1919–1995) from the USA
- Arthur Adams (zoologist) (1820–1878) from Great Britain
- Charles Baker Adams (1814–1853) from the USA
- Henry Adams (zoologist) (1813–1877) from Great Britain
- César Marie Félix Ancey (1860–1906) from France
- Hermann Eduard Anton (1794-1872) from Germany
- Edwin Ashby (1861–1941) from Australia, expert in chitons
- Jean Victoire Audouin (1797–1841) from France
Read more about this topic: Malacologist