This doctoral thesis problematizes and develops a theoretical explanation of the conditions for equal relations in collaboration between public and civil society organizations. The focus is motivated as collaboration, assumed to be characterized by horizontal organizing and equal relations, is promoted by stakeholders across different levels in Sweden and in national policies on civil society. Through a survey and four case studies, the thesis explores how ideas of collaboration are manifested at the local level of municipal departments and civil society organizations: from initiation and establishment to becoming linked to regular municipal operations. Survey responses indicate that municipal collaborations with civil society organizations aiming for horizontal organizingand equal relationships have not manifested in significant ways. Further, ananalysis of Idea-Driven Public Partnerships (IOP) suggests that collaboration is more common where civil society organizations possess the expertise, experience, and legitimacy to act. Collaboration also occurs in a dynamic field of tension. While the collaborations in three cases initially exhibited horizontal organizingand more equal relationships, municipal actors over time took a leading role, aiming for standardization and bureaucratization. To maintain control or influence, the civil society organizations adapted, distanced themselves, or exited. However, regardless of their strategic response, their influence diminished overtime. Through a model for institutional analysis of collaboration, it is illustrated that collaboration tends to reproduce inequality over time. The model also provides an understanding of how collaboration evolves beyond the normative ideals of harmony portrayed in policy and some academic literature.