The need to understand the systems that support ethical health research has long been recognized, but there are limited descriptions of actual health research ethics (HRE) systems. Using participatory network mapping methods, we empirically defined Malaysia's HRE system. 13 Malaysian stakeholders identified 4 overarching and 25 specific HRE system functions and 35 actors internal and 3 external to the Malaysian HRE system responsible for those functions. Functions requiring the most attention were: advising on legislation related to HRE; optimizing research value (...) to society; and defining standards for HRE oversight. Internal actors with the greatest potential for more influence were: the national network of research ethics committees; non-institution-based research ethics committees; and research participants. The World Health Organization, an external actor, had the largest untapped potential for influence overall. In summary, this stakeholder-driven process identified HRE system functions and actors that could be targeted to increase HRE system capacity. (shrink)