A revision is given of the taxa in Malesia and Thailand usually included in Anthoxanthum L. and Hierochloë R. Br. (Gramineae). There are two species, A. horsfleldii (Bennett) Reeder with 7 varieties in Malesia and 1 in Thailand, and A. redolens (Vahl) Royen with 2 varieties in New Guinea. A survey of the characters generally employed to distinguish the genera is given and briefly discussed to show that these give an untenable separation. Some new combinations in Anthoxanthum are proposed.