BACKGROUND: Malnutrition, specifically undernutrition, is a significant global challenge that contributes to nearly half of deaths in children under the age of five. The burden of undernutrition is disproportionately borne by conflict-affected, fragile settings (CAFS); children living in a conflict zone being more than twice as likely to suffer from malnourishment. Community health worker (CHW) models have been employed in CAFS to improve healthcare coverage and identify and treat illnesses. However, there lacks systematic evidence on the impact of CHW models in preventing, identifying, and managing child undernutrition in CAFS. We conducted this review to systematically evaluate evidence of CHW models in preventing, identifying, and managing undernutrition in children under the age of five in CAFS. METHODOLOGY: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting standards. The search strategy was developed using the Population-Intervention-Comparisons-Outcomes-Setting framework as a guide. Searches were performed using Ovid online database search platform, searching the databases of Ovid MEDLINE(R), COCHRANE, Embase Classic, Embase, Econlit, Global Health, SCOPUS, and Social Policy and Practice. Peer-reviewed publications were eligible for inclusion if they evaluated an intervention using a CHW model that aims to prevent, identify, or manage some form of undernutrition in children under five in a CAFS. RESULTS: We identified 25 studies-spanning 10 countries-that were included in the systematic review. CHW models were implemented alongside a variety of interventions, including behaviour change communication, supplementary foods, nutrition counselling, and integrated community health programmes. Key barriers in implementing successful CHW models include disruption of programmes due to active conflict, states of emergency, militancy, or political unrest; weak links between the community-based interventions and public health system; weak health system capacity that impeded referral and follow-ups; and cost of care and care-seeking. Key facilitators include CHWs connection to the community, close proximity of programmes to the community, supervision, and investment in high quality training and tools. CONCLUSIONS: The findings suggest that CHW models may be effective, cost-effective, acceptable, feasible, and scalable in the prevention, identification, and management child undernutrition in CAFS. The study findings also confirmed a need for greater evidence in the field. These findings may inform policymaking, programme implementation, and design to strengthen best practices for CHW models addressing child undernutrition in CAFS.