<p>Childhood vaccine-preventable diseases are the leading cause of under-five mortality and morbidity in Nigeria. While many studies have explored individual factors that influence complete vaccination in Nigeria, most have primarily focused on maternal-related factors. This study employed the health belief model to investigate the influence of paternal characteristics on full childhood vaccination in Nigeria. Using the 2018 Nigeria Demographic Health Survey, a nationally representative cross-sectional survey that adopts a stratified, two-stage cluster design sampling technique, multinomial logistic regression analysis was conducted to examine the influence of paternal factors on full childhood vaccination (<i>n</i> = 2098). Findings revealed that achieving full vaccination was significantly predicted by a higher paternal education level and joint decision-making. Children of fathers with no education were 77% less likely to be fully vaccinated than to be unvaccinated compared to fathers with secondary education, and when fathers alone made health decisions, their children were 47% less likely to be fully vaccinated than to be unvaccinated compared to when couples together made health decisions (<i>p</i> &lt; .05). These results highlight the crucial role of male partners in the family dynamic. Recognizing the importance of fathers is essential for designing effective interventions, emphasizing the need to educate fathers about vaccination importance, and promoting collaborative decision-making between partners to instill healthy choices that benefit their children.</p>