Organizational members are likely to face more than one paradox simultaneously. In order to conceptualize how paradoxes are knotted together and influence each other, paradox research needs to better account for dynamics and integrative aspects. In this paper we introduce the System Dynamics approach which we apply to coopetition for sustainability. Via an in-depth case study of a large-scale Swedish project to create a brand new, sustainable residential area, we are able to trace how the two paradoxes (coopetition and sustainability) influence each other but also take turns in dominating the processual unfolding. Our study contributes by developing and illustrating an approach to conceptualizing knotted paradoxes in general and coopetition for sustainability in particular.