Abstract: There are many forms of shared activity, from those pursued by informal groups spontaneously, to actions performed by highly coordinated dyads of individuals in face-to-face situations, to institutional actions spread in space and time. Following some recent accounts of shared intentionality, I argue that the ‘sharedness’ in shared intentionality is best exemplified in cases of joint action informed by joint practical reasoning, in which agents deliberate together about the best means to pursue an action and then act upon such deliberation. I argue that joint activities of the relevant sort share a normative structure given by practical, means‐end structures, that are commonly known by plural agents ‘we’. By analysing a larger set of examples of shared activities, I argue that these structures are exemplified in various different species of joint activity when no explicit deliberation is involved. Those range from intersubjective spontaneous coordinated activities that involve mutual tracking, mutual responses and mutual attunement - joint improvised dance falls under this category - to more complex joint activities as the ones scaffolded by instructions or specialized background knowledge - as when playing music together by following a musical score or in case of jazz group improvisation -and social norms and institutions, e.g. when playing chess, paying a check at the Bank Cashier, or driving through a crowded street. An interesting upshot of this approach is that shared intentionality in this view can be seen as coming in a variety of degrees of cognitive complexity, ranging from minimal forms of interaction and mutual understanding, to very demanding forms that presuppose linguistic abilities for communication and joint practical reasoning. I end the talk by discussing how this account speaks to developmental evidence on how shared intentional capacities unfold in early infancy.