This paper considers patient and public involvement (PPI) in health economics research and how this might be facilitated. PPI refers to research carried out ‘with’ or ‘by’ members of the public and is now an important aspect of health research policies internationally. Patients and members of the public can be involved in all stages of the research cycle, from establishing whether the topic is important to influencing details of study design, wording of patient-facing documentation and interpretation and dissemination of findings. PPI has become commonplace in health services research. In the context of clinical trials, it has become imperative, with, for example, patients and members of the public informing the selection of outcome measures and recruitment methods, and qualitative research is frequently steered by PPI input regarding the content of interview topic guides and the interpretation of study findings. It is less common for PPI to be explicitly reported in the economic components of health services research. However, we argue that involvement is no less important in this area. The fundamental rationale for involving people in research is that it promotes democratic principles, research quality and relevance to service users. These arguments equally apply to health economics as to other health research disciplines. Our overarching aim in this paper is to show how health economic research might be informed by PPI. We report our experiences of PPI via case studies in child health, reflect on our learnings, and make suggestions for future research practice.