The present study investigated whether teacher beliefs (self-efficacy and attitudes) mediate the impact of professional background on child-centred educational practice. We specifically investigated whether teacher beliefs related to self (self-efficacy) are a stronger predictor of educational practice than teacher beliefs related to teaching approach (attitudes). A total of 265 professionals from different early education and care settings (i.e., centre-based daycare, family-based daycare, and educational playgroups) in Switzerland participated in the study. A self-report questionnaire was developed to assess professionals’ self-efficacy, attitudes and educational practice in terms of child-centredness. The results confirm the factorial validity of the questionnaire. Self-efficacy positively predicted educational practice, while professionals’ attitudes were not associated with educational practice. Further, the positive effect of domain-specific knowledge on educational practice was mediated by self-efficacy. Finally, family daycare providers reported lower self-efficacy and lower levels of child-centred educational practice than other professionals. The present study emphasises the role of professionals’ self-efficacy in the context of delivering high-quality childcare and child-centred education in early childhood. The results suggest that promoting knowledge of teaching approaches may be a promising way to promote early childhood educators’ child-centred educational practice through increasing their self-efficacy.