The 5th International Tunicate Meeting (ITM5) was held at the Okinawa Industry Support Center (Naha, Okinawa, Japan) from June 21 to 25, 2009, with support from the Okinawa Institute of Science and Technology (OIST) and the Inoue Foundation for Science. Tunicates are defined as deuterostome metazoans that have notochord in the tail at one point or at all times during their life. Presence of a cellulosic integument is also a synapomorphy for this taxon, which consists of three classes: Ascidiacea, Thaliacea, and Appendicularia. Ascidians, the largest class, are always sessile, while thaliaceans and appendicularians are pelagic throughout their life. Many unique and interesting data sets are available that facilitate research on tunicates, such as full-genome information for Ciona, numerous ESTs with in-situ hybridization images, well-documented cell lineages during embryogenesis, among many others. The present note gives an overview of the topics from the sessions and plenary lectures of ITM5. As seen below, the tunicate scientific community is worldwide, with flexible networks among tunicate biologists, and a particularly wide range of species diversity and phenomena were presented during ITM5. ITM6 is planned for 2011 in Montreal.