James Nathaniel Halbert was an Irish entomologist. He was born 30 August 1872 and died 7 May 1948 in Dalkey, Dublin, Ireland.
In 1892, Halbert began work at the Science and Art Museum, in Dublin (now the National Museum of Ireland). He was appointed Technical Assistant in 1904 and then Assistant Naturalist, in place of George Herbert Carpenter, a few months later.His first publications were on Coleoptera and appeared in the Irish Naturalist starting in 1892. He also worked with other insects, mainly Neuroptera and Hemiptera. He also worked with fresh water mites, described more than forty insect species and subspecies from Ireland, and was the author of several new genera.