Breastfeeding is widely recognized as a cornerstone of infant survival and immune development, particularly in low- and middle-income countries like Nigeria. This systematic review examines the prevalent breastfeeding practices among Nigerian mothers and evaluates their influence on the immune development of infants. Drawing from peer-reviewed journal articles, national reports, and global health organization databases, the review synthesizes evidence on exclusive breastfeeding, early initiation, duration of breastfeeding, and complementary feeding within the Nigerian context. The findings reveal that while many Nigerian mothers are aware of the benefits of breastfeeding, socio-cultural beliefs, economic pressures, limited maternal education, and inadequate healthcare support often hinder optimal practices. Exclusive breastfeeding for the first six months and early initiation of colostrum feeding were found to significantly contribute to improved immune responses in infants by reducing incidences of infections such as diarrhea, pneumonia, and sepsis. The study underscores the need for integrated health education campaigns, supportive workplace and community structures, and strengthened health system interventions to improve breastfeeding outcomes. It concludes that enhancing breastfeeding practices in Nigeria could substantially improve child health indicators and reduce under-five mortality.