Effectively designed complaint handling systems play a key role in enabling vulnerable consumers to complain and obtain redress. This article examines current research into consumer vulnerability, highlighting its multidimensional and expansive nature. Contemporary understandings of consumer vulnerability recognize that the interaction between a wide range of market and consumer characteristics can combine to place any individual at risk of vulnerability. While this broad definition of consumer vulnerability reflects the complex reality of consumers' experiences, it poses a key challenge for designers of complaint handling systems: how can they identify and respond to an issue which can potentially affect everyone? Drawing on current research and practice in the United Kingdom and Australia, the article analyses the impact of consumer vulnerability on third party dispute resolution schemes and considers the role these complaint handling organizations can play in supporting their complainants. Third party complaint handling organizations, including a range of Alternative Dispute Resolution services such as ombudsman organizations, can play a key role in increasing access to justice for vulnerable consumer groups and provide specific assistance for individual complainants during the process. It is an opportune time to review whether the needs of consumers at risk of vulnerability are being met within complaint processes and the extent to which third party complaint handlers support those who are most vulnerable to seek redress.Empowering vulnerable consumers to complain presents specific challenges. The article discusses the application of a new model of consumer dispute system design to show how complaint handling organizations can meet the needs of the most vulnerable consumers throughout the process. K E Y W O R D S alternative dispute resolution, complaint handling, consumer vulnerability, dispute system design, third party complaint handlers, vulnerable complainants wileyonlinelibrary.com/journal/ijcs Int J Consum Stud. 2017;41:638-646.