BACKGROUND: Patient and public involvement and engagement (PPIE) is essential throughout the research cycle, but a one-size-fits-all approach does not suit all study types. Health data research presents several unique challenges, including ensuring data transparency and security. Thus, PPIE guidance should ideally define specific tasks to reduce the likelihood of tokenistic involvement. We therefore aimed to develop actionable, task-focused guidance for PPIE in health data research. METHODS: We used a consensus development process. We generated a list of potential PPIE tasks in health data research from existing literature informed by discussion with expert witnesses. We convened a consensus panel of nine members, comprising PPIE participants with varying experiences of PPIE and data research, PPIE professionals and health researchers. The panel first rated their agreement with tasks independently online and then discussed disagreements during an in-person meeting, after which all tasks were re-rated. We calculated median scores and refined a final set of tasks. RESULTS: We identified 29 tasks across six domains of the research cycle: (1) prioritising and commissioning research; (2) planning research projects; (3) delivering research; (4) interpreting research; (5) sharing and using research knowledge; and (6) evaluating research. Consensus was reached on 25 tasks in the first round. Initial disagreements, particularly around planning research projects and monitoring data privacy, were resolved following structured discussions. Consensus and support were achieved for all 29 tasks following the second round. CONCLUSIONS: PPIE participants expressed a strong desire to be involved in all aspects of the research cycle. We offer a framework of actionable PPIE tasks for health data research and invite further development and evaluation. PATIENT AND PUBLIC CONTRIBUTIONS: PPIE participants were involved shaping the project idea and design, draughting a list of PPIE tasks, rating and discussing the importance of PPIE tasks and co-writing the publication.