Since their recent introductions into Florida waters, three nonnative species [Perna viridis Linnaeus, 1758 (Asian green mussel), Mytella charruana d'Orbigny, 1846 (charru mussel) and Megabalanus coccopoma Darwin, 1854 (pink titan acorn barnacle)] have expanded both north and south along the Atlantic coast. Very little research has been done to understand how these nonnative species interact with the native eastern oyster (Crassostrea virginica Gmelin, 1791), which is a keystone species that provides important ecological services and economic benefits. To test the potential effects of P. viridis, M. charruana and M. coccopoma on C. virginica, I addressed the following questions: 1a) Does the presence of nonnative species decrease oyster larval settlement? 1b) Do oyster larvae avoid settling on oyster shells to which nonnative species are attached? 2a) Do nonnative species decrease survival of juvenile oysters (spat)? and 2b) Do nonnative species hinder spat growth? My manipulative experiments showed that the tested nonnative species influenced settlement, growth and survival of C. virginica in unique ways. Megabalanus coccopoma decreased the total number of settled oyster larvae, but did not influence larval preference or survival and growth of spat. Perna viridis negatively influenced larval settlement and oyster larvae avoided settling on shells of P. viridis. Mytella charruana had no influence on the total number of settled larvae but oyster larvae avoided settling on oyster shell with M. charruana or on the mussel shells themselves. Furthermore, both nonnative mussels negatively affected the survival of juvenile oysters, but only M. charruana reduced spat growth. These three nonnative species should be classified as invasive species because all had negative effects on the native oyster C. virginica.