The Ilhabela State Park is a state park in the state of São Paulo, Brazil. It protects an area of Atlantic Forest on an archipelago in the South Atlantic off the northeast coast of the state, including most of the mountainous island of São Sebastião.

A state park in Brazil is a legally defined type of protected area operated by one of the states. Their goal is to preserve important or beautiful natural ecosystems. Public access is allowed subject to regulations defined by the responsible agency.