Introduction Becoming a parent presents profound changes and numerous challenges, notably the necessity for reliable information regarding their child’s health. Given the overabundance of information available today, it is important for parents to acquire the skills necessary to find, understand, evaluate and apply health information. Research demonstrates that this ability, known as parental health literacy (PHL), is crucial for developing and maintaining a healthy lifestyle during childhood. However, there is currently no reliable instrument for measuring PHL in the field of prevention and health promotion. This paper presents the development and validation of a new questionnaire designed to assess parents’ ability to process health-related information to support the healthy development of their children aged 3–6 years. Methods and analysis The development of the item pool is based on Sørensen et al’s conceptualisation of general health literacy (finding, understanding, evaluating and applying health information). Empirical findings suggest that communication with healthcare providers and the social network represents another important skill area for parents and is therefore included as an additional subscale. The questionnaire will be developed in four stages, including a literature search and analysis, expert consultations via Delphi study, cognitive interviews with parents and a validation study. The validation study uses exploratory (EFA) and confirmatory factor analysis (CFA) for construct validity, first identifying test dimensions through EFA, then confirming these dimensions with CFA to ensure the factor structure aligns with theoretical expectations. This methodology, alongside reliability and correlational analyses, seeks to assess the questionnaire’s validity and reliability, expecting strong correlations with existing related constructs. Ethics and dissemination Ethical approval was obtained from the Ethics Committee of Fulda University of Applied Sciences. All participants receive a consent form together with the study information, in which they give their written consent to the storage, processing and linking of all data collected. The results of the study will be presented at national and international conferences and published in specialist journals.