This work examines how co-leaders can recognize and address tensions in their joint leadership work and use them as a resource for development. Based on the author's own co-leadership experience and supplemented by interviews, workshops, and co-creation formats, she designs three “interstitial spaces” in which co-leaders can reflect on their practice and make tensions visible. Theoretically, she anchors the topic in models of self-leadership, psychological safety, ambiguity tolerance, and reflexive practice, and links these with strategic design approaches such as iterative work, perspective shifts, and the creation of spaces of possibility. As a result, she develops the co-leadership tension loop and two practical artifacts—the peer format co:labor and the card set spannungs:loop—which are designed to help co-leaders work through tensions systematically and productively and further develop their joint leadership.