Transforming Housing is a Melbourne action research partnership facilitated by the University of Melbourne, involving local and state government, private and non-profit developers, private and philanthropic investors, and affordable housing advocates. The current focus of the research is on exploring options in terms of better policy and investment mechanisms, in order to move partners towards actions. The purpose of this paper is to summarize how affordable housing partnerships in three cities with similar planning regimes, population pressures, affordability dilemmas, and housing typologies, are developing innovative approaches, and derive lessons from these partnerships for Melbourne.