A new species of nomioidine Halictidae in the genus Ceylalictus Strand, 1913, is described and illustrated from Thailand as Ceylalictus (Atronomioides) bantoonei Warrit & Michener. The species is distinguished by the combination of the following features: black integument (faintly greenish on the scutum of the female), head longer than broad, inner margin of the eyes with strong emargination, and glossa including basal part as long as head.