CONTEXT: Although effective health and nutrition interventions for reducing child mortality and morbidity exist, direct evidence of effects on cognitive, motor, and psychosocial development is lacking. OBJECTIVE: To review existing evidence for health and nutrition interventions affecting direct measures of (and pathways to) early child development. DATA SOURCES: Reviews and recent overviews of interventions across the continuum of care and component studies. STUDY SELECTION: We selected systematic reviews detailing the effectiveness of health or nutrition interventions that have plausible links to child development and/or contain direct measures of cognitive, motor, and psychosocial development. DATA EXTRACTION: A team of reviewers independently extracted data and assessed their quality. RESULTS: Sixty systematic reviews contained the outcomes of interest. Various interventions reduced morbidity and improved child growth, but few had direct measures of child development. Of particular benefit were food and micronutrient supplementation for mothers to reduce the risk of small for gestational age and iodine deficiency, strategies to reduce iron deficiency anemia in infancy, and early neonatal care (appropriate resuscitation, delayed cord clamping, and Kangaroo Mother Care). Neuroprotective interventions for imminent preterm birth showed the largest effect sizes (antenatal corticosteroids for developmental delay: risk ratio 0.49, 95% confidence interval 0.24 to 1.00; magnesium sulfate for gross motor dysfunction: risk ratio 0.61, 95% confidence interval 0.44 to 0.85). LIMITATIONS: Given the focus on high-quality studies captured in leading systematic reviews, only effects reported within studies included in systematic reviews were captured. CONCLUSIONS: These findings should guide the prioritization and scale-up of interventions within critical periods of early infancy and childhood, and encourage research into their implementation at scale.