I will shed light on the phenomenon of collective intentionality, which, in the philosophical, cognitive sciences and neurosciences debate, is often confused with similar yet diverse phenomena, i.e. with inter-subjective intentionality, also called social cognition, and with social intentionality. In order to elucidate the phenomenon of collective intentionality, I will present a taxonomy of collective, inter-subjective and social intentionality, and consider a thesis about shared intentionality. The taxonomy intends to show that although collective, inter-subjective and social intentionality are very close phenomena, nonetheless they are different types of intentionality, and that, like individual intentionality, collective and inter-subjective intentionality involve different kinds of intentionality—practical, affective and cognitive—which have to be distinguished The sharing thesis, I will argue for, maintains that collective intentionality is a shared intentionality in a very strong sense of the term «sharing», a sense that implies some essential conditions, which are not required in the cases of inter-subjective and social intentionality. Finally I shall point out hat inter-subjective intentionality is the basis and the necessary condition for collective and social intentionality.