Introduction: Involving patients and the public in design, conduct and dissemination of research has gained momentum in recent years. While methods to prioritize research on treatment uncertainties have been successfully applied for various disease entities, patient and public involvement has not been prominent to prioritize research in health literacy (HL). This study aimed to set up a participatory process on identifying HL research gaps from a parental perspective in two use cases: early childhood allergy prevention (ECAP) and COVID-19 in children with allergies (COVICAL). Methods: To prepare and empower parents, we developed and provided preparatory webinars, introductory materials, i.e., factsheets and a brochure, and a scientific podcast with seven episodes. Recruitment was carried out by our cooperation partner German Allergy and Asthma Association e. V., via local day care centres and paediatricians as well as via snowballing. The identification of research gaps took place within five workshops with n= 55 participants, four face-to-face-workshops across Germany, one online workshop. Research ideas and needs were reviewed for overlap and redundancy and compared to the existing research state of the art. Results: More than 150 initial research ideas and needs were collected which after review were reduced to a total of 37 ECAP, 33 COVICAL and 7 generic HL research questions. These were particularly related to the ease of finding and presenting good quality health information, information environment, health communication, professional education, and HL testing. Conclusions: Involving parents in the formulation of HL research priorities proved to be challenging but feasible. Research ideas often reflect wishes directed at health professionals and the health system, i.e., organizational, and systemic HL. An e Delphi process will follow to elicit the TOP 10 research priorities in each use case. This project will help to plan patient/parent centred HL research in ECAP and COVICAL. Keywords: participatory health research; health literacy research; research gaps; patient and public involvement; co-researcher; early childhood allergy prevention; COVID-19 in children with allergies