Alexandre Arsène Girault (/ʒɪəˈroʊ/ zhee-ROH; 9 January 1884 – 2 May 1941) was an American entomologist specializing in the study of chalcid wasps. An eccentric and controversial figure, Girault was also a prolific and dedicated entomologist. He published more than 325 papers and described over 3000 new taxa from Australia.