Organizations in the not‐for‐profit (NFP) sector are increasingly collaborating with other organizations to mutually raise overall joint value created. However, literature on inter‐organizational collaborations in the NFP sector lacks a clear, empirically proven understanding about which factors drive such joint value creation and whether and how these factors and their effects differ for the two parties involved. Based on the relational view and an analysis of 121 partnership dyads, we identify that some factors governing the successful creation of joint value differ for the two partners while others are relevant to both parties. Those latter factors, in turn, differ in their effects on the respective outcome.