In this study, we investigate community structure in day geckos (genus Phelsuma) in the Indian Ocean. Much of what we know about communities of diurnal arboreal lizards comes from studies of Caribbean Anolis. Phelsuma in the Indian Ocean are ecologically similar to Anolis but not closely related. Using field observations and an experiment, we test three hypotheses for Phelsuma communities, all derived from work on Anolis: (1) Phelsuma species richness will be correlated with the diversity of available perches, (2) sympatric species will partition their habitat use, shifting their habitat use depending on which other species of Phelsuma are present, and (3) experimentally removing individuals of one species will lead to changes in the microhabitat use and/or abundance of sympatric congeners. We find support for all three hypotheses. We also describe some unique aspects of Phelsuma communities, such as partitioning of palm vs. non-palm trees. This study identifies some potentially general features of diurnal arboreal lizard communities, and suggests that some aspects of community assembly might be repeatable.