Open innovation is a viable strategy to solve wicked problems. However, the complexity of these types of problems renders the management of open innovation initiatives (even) more difficult. How can managers make open innovation for complex or even wicked problems work? This article examines case studies of open innovation initiatives adopting a health care service innovation. It uses the proximity framework to identify several ways in which open innovation barriers can be overcome despite their complexity. The case study findings show how partners leverage their differences to the benefit of service innovation in the face of wicked problems.