The factors contributing to biodiversity of terrestrial gastropods on Mo’orea, French Polynesia are investigated. Gastropods are sampled from four native forests of predominately Hibiscus tiliaceus, and four nonnative forests of predominately Falcataria moluccana within two elevational ranges. It is determined that the type of forest has an effect on the species composition of that habitat. Additionally, it is determined that elevation is a determinant in relative species composition. An additional variable possibly contributing to species distribution is the predatory detection of the introduced flatworm, Platydemus manokwari, by two predominant species of this study. This is primarily a study on the current biodiversity of a vastly neglected group of molluscs on island of Mo’orea.