Despite a growing recognition internationally that children have a right to participate in matters that affect their lives, they are not always involved in decision-making processes concerning their health care. There is a lack of information on how parents influence children's participation in this decision making. This study explored the roles parents assume in processes regarding their children's participation in communication exchanges and decision making in a paediatric oncology unit in Malaysia. This study adopted a focused ethnography design within a constructivist research paradigm. Participant observations and semi-structured interviews were conducted with 21 parents, 21 children and 19 nurses in a paediatric oncology unit in Malaysia. All observation fieldnotes and interview recordings were transcribed verbatim. A focused ethnographic data analysis technique was performed to analyse the data. Three themes emerged regarding parents' roles in the communication and decision-making processes involving their children: i) facilitators of communication; ii) communication brokers and iii) communication buffers. Parents controlled decision-making processes concerning their children, while children preferred and welcomed parents as consultants in the decision-making processes regarding their health care.