In temporally extended agency, past, present, and (normally) future thought and action are tied together in distinctive ways. In shared intentional activity, the thoughts and actions of the participants are tied together in distinctive ways. My conjecture is that a fundamental ground of these human capacities for temporally extended and shared intentional agency are human capacities for planning agency. The conceptual, metaphysical, and normative resources in play in our planning agency provide a backbone of our temporally extended and shared intentional agency.