The leaf epidermis of 23 species of Psychotria wasstudied. Leaf samples were prepared using the peeling technique, stained with 1% safranin O in 70% ethanol, and observed under a compound light microscope. The results revealed that the general epidermal cell shapes of Thai Psychotria species are polygonal, irregular, or a mixture of both within the same species. Anticlinal walls are straight, curved or a combination of both. Cuticular sculpturing patterns are reticulate, striate orsmooth. Stomata are paracytic, paralelocytic, or a mixedparacytic and paralelocytic. Trichomes are articulate-pluricellular, cylindrical-pluricellular and conical-unicellular types. Idioblasts andinclusions are found in the form of secretory sac, prismatic crystals, raphide crystals and crystal sand. The results showed that leaf epidermal characteristics can be used for identification of some species or for grouping species. The characters that are useful for this purpose are the presence and type of trichomes, the type and pattern ofcuticular sculpturing, as well as the presence of idioblasts and inclusions.