Social movement coalitions are a vital component within the dynamics of political mobilization. While previous research has established why and how coalitions emerge and dissolve, how they are maintained and the outcomes they generate have been less explored, especially in housing studies. This research contributes to the study of movement coalitions through an empirical examination of the dynamics of how coalitions interact, cooperate, and sustain alliances, in addition to exploring the outcomes that are produced as a result of these coalitions. It draws upon a comparative approach of housing coalitions in Dublin and Lisbon, where local housing groups have played a critical role in protesting against housing injustices and in articulating alternative policy solutions to the housing crisis. In mapping the diversity of coalition members, this research finds that tolerance for difference and negotiation capacity impacts how long coalitions last as well as the outcomes that they lead to. This study contributes to the study of coalitions by analyzing the relation- ship between outcomes and the mechanisms which sustain coalitions using a comparative framework.