Background <p>Vaccination advice from physicians is essential for the prevention of vaccine-preventable diseases. However, the specific constructs underlying parental decision making among vaccine-hesitant and vaccine-refusing parents remain poorly understood.</p> Objective <p>The aim of this study was to explore the constructs underlying parental decisions about vaccination practices, including those leading to nonvaccination, and to examine the role of medical advice on vaccination in influencing these decisions.</p> Methods <p>Focus group discussions were conducted with 11&#xa0;mothers who had at least one incompletely vaccinated or unvaccinated child aged 18–36&#xa0;months. The discussions were audio recorded, transcribed verbatim, and analyzed using Mayring’s qualitative content analysis. The participation pyramid model by Straßburger &amp; Rieger (2019) was adopted as a&#xa0;theoretical framework and linked to the findings.</p> Results <p>All participants showed skepticism or outright refusal of vaccination. Their decisions to deviate from the STIKO (German: <i>Ständige Impfkommission</i>)-recommended vaccination schedule were mainly based on self-initiated research and individual risk assessment of their children. This self-acquired parental expertise often conflicted with the medical knowledge provided by health professionals. In addition, three distinct typologies of parental decision making were identified: (1)&#xa0;the medical paternalistic type (vaccine-accepting parents), (2)&#xa0;the participatory type, and (3)&#xa0;the self-determination type (vaccine-refusing parents).</p> Conclusion <p>The findings provide valuable insights into the implementation of participatory medical vaccination counselling aimed at (1)&#xa0;enhancing communication between parents and healthcare providers and, consequently, (2)&#xa0;increasing vaccine acceptance. Furthermore, medical vaccination counselling must be emphasized within the sociolegal framework and not viewed solely from a&#xa0;medical perspective.</p>