The high morbidity and mortality rates among neonates in Nigeria highlight the urgent need to strengthen nurses’ understanding of developmental care principles. This study investigated the effect of an educational intervention on nurses’ knowledge of the components of the Synactive Theory of Development in selected neonatal intensive care units (NICUs) in Lagos State. A quasi-experimental one-group pre- and post-intervention design was adopted, involving 58 nurses selected through multistage sampling. A validated structured questionnaire assessed knowledge before and after the intervention. Data were analyzed using descriptive and inferential statistics at a 0.05 significance level. Findings revealed that nurses initially demonstrated moderate knowledge across all components of the theory, with the weakest understanding observed in the attention and self-regulatory subsystems. Following the intervention, there was a notable improvement in knowledge across all five components (autonomic, motor, behavioral, attention, and self-regulatory systems) confirming the effectiveness of the educational program. The Analysis of Variance (ANOVA) further indicated a significant difference between pre- and post-intervention mean scores, suggesting that structured training effectively enhanced comprehension of the Synactive Theory. The study concludes that educational interventions are valuable for improving nurses’ theoretical and practical understanding in neonatal care and recommends ongoing training and curriculum integration to sustain competence and improve neonatal outcomes. Keywords: Educational intervention, Synactive Theory, Neonatal care, Nurses’ knowledge, Developmental care,
OGUNDEKO et al. (Sun,) studied this question.