This thesis aims to provide insights on how private-sector inter-organizational collaboration creates interaction and synergistic value towards sustainability. Value propositions are directed towards individuals, organizations and society at large. To achieve this purpose, an explorative, in-depth case study on the NextWave initiative is conducted to address the sustainability challenge of marine plastic pollution. An abductive research approach is applied, matching main theories of both private-sector partnerships and value co-creation with empirical data gathered through semi-structured interviews with NextWave members. The study looks at individual as well as collaborative activities leading to the cocreationof interaction and synergistic value. It is further analyzed, how these created values lead toexternal system change towards sustainability. Key findings are limited to the case of NextWave as the intent of the study is an initial exploration of the topic. The data leads the authors to an affirmative conclusion, delivering a number of activity and process examples that foster collaboration and promote interaction and synergistic value. That, in turn, allows for system change and a more sustainable development. Therefore, this thesis makes valuable contributions to the theoretical knowledge of collaboration and value creation. Additionally, a conceptual and analytical framework based on contemporary literature contributes to the body of knowledge as well as allows practical application.