Strategies to increase transparency and accountability often include complaints mechanisms by which organisations can respond to individual suspicions of corruption and other grievances. This Brief discusses how complaints mechanisms have been used by the vigilance director for health’s office in Karantaka state, India, and by Partners in Health – an international NGO that manages health service delivery projects. These cases suggest that complaints mechanisms should be reinforced by political and judicial systems that support investigation and prosecution. A focus on individual level grievances should be balanced with institutional reforms that address management and accountability problems that complaints may reveal.