Psychological ownership (PO) is important for organisational climate and outcomes, yet, little is known about collective forms of PO in emerging entrepreneurial teams. Based on an in-depth study of a new venture team over three years, we sketch a process model of collective PO development. While studies on individual PO in established organisations highlight individual needs in triggering processes of PO development, our study indicates the importance of temporal, role-based, and input-based alignment of interpersonal processes for the emergence of collective PO in new venture teams. We discuss insights for research on new venture teams and research on small groups.