The taxonomic status of three nominal species in the synonymy of the wide ranging Australo-Papuan snake Dendrelaphis calligaster (Günther, 1867) was investigated. Dendrophis meeki Boulenger, 1895 was shown to represent an insular population of D. gastrostictus instead of D. calligaster and is therefore transferred to the synonymy of the former. A description is given of the syntypes of D. meeki. Dendrelaphis calligaster distinguendus Meise & Hennig, 1932 was found to be fairly distinct from other populations of D. calligaster. However, it is not diagnosable and may not represent an independently evolving lineage. Therefore, its placement in the synonymy of D. calligaster is maintained. A neotype (ZMB 24024) is designated and described because the original types were destroyed during World War II. Finally, Dendrophis salomonis Günther, 1872 was demonstrated to be indistinct from the D. calligaster metapopulation. It too is maintained in the synonymy of D. calligaster. A description of the syntypes is provided.