In recent years, competition has emerged as a central theme in international mediation as an increasing number of mediation actors seek opportunities to engage in peacemaking. At the same time, mediation coordination mechanisms, such as Groups of Friends, have been become standard practice in international peacemaking. This paper seeks to make sense of the dynamics of competition and cooperation in peace mediation today. To this end, it considers three case studies of post-Cold War peace processes: Sudan (North-South, 1994–2005), Kenya (2008) and Madagascar (2009, ongoing). On the basis of interviews with experts directly involved in these processes, it identifies three driving forces of competition: clashing interests between states, overlapping mandates of mediation actors, and disagreements over the normative basis of international politics. These factors risk undermining peace processes unless the mediators take steps to prevent or mitigate the negative effects of competition. This can be done through ‘hierarchical coordination’, where a recognized authority takes the lead and allocates roles to other actors, or through ‘networked-based cooperation’, where partners decide on a division of labour.