Advancements in mental health research, social changes and policy developments have led to the emergence of new forms of research partnerships, which bring together research institutions, public companies and lay people as partners in the same research project. In this paper, we argue that partnerships comprised of industry, academia and people with experience of mental illness may present practical and ethical challenges that affect the conduct of research and undermine public trust in research collaborations. We outline a number of ethical problems from the motivation to combine competing interests and values of these diverse research partners. We argue that while critical perspectives on each of the partnership forms outlined above exist in the literature, the combination of industry, research and PPI actors in partnership in mental health research has not received sufficient scrutiny. We suggest that a robust ethical approach is needed to properly substantiate the value of such research partnerships, to inform practical and ethical guidance on potential conflicts and to facilitate productive collaborative research.