Introduction The Informed Health Choices (IHC) project developed learning resources to teach primary school children (10 to 12-year-olds) to assess treatment claims and make informed health choices. The aim of our study is to explore the educational context for teaching and learning critical thinking about health in Spanish primary schools. Methods During the 2020-2021 school year, we will conduct 1) a systematic assessment of educational documents and resources, and 2) semi-structured interviews with key education and health stakeholders. In the systematic assessment of educational documents and resources, we will include state and autonomous communities’ curriculums, school educational projects, and commonly used textbooks and other health teaching materials. In the semi-structured interviews, we will involve education and health policy makers, developers of learning resources, developers of health promotion and educational interventions, head teachers, teachers, families, and paediatric primary care providers. We will design and pilot a data extraction form and a semi-structured interview guide to collect the data. We will perform a quantitative and a qualitative analysis of the data to explore how critical thinking about health is being taught and learned in Spanish primary schools. Conclusion We will identify opportunities for and barriers to teaching and learning critical thinking about health in Spanish primary schools. We will formulate recommendations-for both practice and research purposes-on how to use, adapt (if needed), and implement the IHC resources in this context.