The cuticular characters of the leaves of all Malesian species belonging to 25 genera of the Icacinaceae and those of Pennantia from Australia and New Zealand and some taxa from Continental Asia have been studied and are described in detail. Five stomatal types and nine different hair types are recorded for this part of the family. Haberlandt’s interpretation of the slender papilla-like hairs of Gonocaryum as hydathodes is challenged. Penetrating asteroscleroids in the cuticular flanges of two Stemonurus species are reported for this family for the first time. A synoptical key to the genera on the basis of cuticular characters only is given. The diagnostic and taxonomic value of the characters used is discussed. Taxonomic implications of this study are the indication of a close relationship between Phytocreneae and lodeae (all climbers), the isolated position of the genera Platea and Gonocaryum, and the impression that Mappianthus should be treated as a genus separate from Iodes. The combined characters of indumentum and stomatal type do not show an absolute correlation with the levels of specialization found in wood- and nodal anatomy for this family by Bailey and Howard. The distribution of stomatal types over the genera, however, suggests that the paracytic and anomocytic types are primitive for Icacinaceae and that the cyclocytic and anisocytic types are more derived.