Sustainable agri-food value chains increasingly depend on smallholders' capacity to participate in markets in stable, remunerative and upgrade-oriented ways. Yet in conflict-affected and politically constrained settings, market integration is weakened by mobility restrictions, insecure logistics, payment disruptions, volatile input systems, thin market information and uncertain enforcement. This integrative review synthesizes peer-reviewed evidence on how these constraints reshape smallholder integration across agricultural value chains and how governance and institutional arrangements can reduce, or sometimes reproduce, market exclusion. A structured narrative search of Scopus, Web of Science and Google Scholar was organized around smallholders, market integration, agricultural value chains and conflict or political constraint. Evidence was coded across seven diagnostic dimensions: inputs and supplies, production capacity and technology, end-markets and trade, value chain governance, sustainable production and energy use, value chain finance, and the enabling business and socio-political environment. The synthesis shows that governance and institutions operate as a conditional bridge: cooperatives, contracting, trader coordination, market-support institutions and public enabling arrangements can lower transaction costs and stabilize exchange, but only where transparency, credible enforcement, fair risk-sharing and protection against opportunism are present. The review concludes with a measurement-focused research agenda for resilient and sustainable value-chain integration under constraint.

Sustainable agri-food value chains depend on the capacity of smallholders to participate in markets in stable, remunerative and upgrade-oriented ways, yet in conflict-affected and politically constrained settings this capacity is weakened by mobility restrictions, insecure logistics, payment disruption, volatile inputs, thin market information and uncertain enforcement. This study aims to explain how such constraints reshape smallholder market integration and under what conditions governance and institutional arrangements stabilize, rather than reproduce, market exclusion. An integrative review was conducted following established methodological guidance. A structured search of Scopus, Web of Science and Google Scholar, extended by citation tracing, returned 821 records; after de-duplication and two-stage screening against explicit eligibility criteria, 44 studies were retained, of which 35 empirical studies form the evidence corpus. Each study was coded with a five-field extraction matrix across seven diagnostic dimensions—inputs and supplies, production capacity and technology, end-markets and trade, value-chain governance, sustainable production and energy use, value-chain finance, and the business and socio-political environment—and appraised for methodological quality with the Mixed Methods Appraisal Tool, so that heterogeneous designs were weighted rather than treated as equivalent. The synthesis shows that the most binding constraints are transactional and institutional rather than purely technical, and that governance operates as a conditional bridge: cooperatives, contracting, trader coordination, market-support institutions and public enabling arrangements lower transaction costs and stabilize exchange only where transparency, credible enforcement, fair risk-sharing and protection against opportunism are present; where these are absent, the same arrangements shift risk onto farmers. The review derives a measurement-focused, equity-sensitive research agenda for resilient and sustainable value-chain integration under constraints.