Participation of smallholder producers in market-oriented production holds potential for diversifying their incomes and increase agriculture productivity hence promoting food security and poverty eradication. However, participation of smallholders in commercialized production is generally limited by various institutional, technical and investment constraints along the supply chain. Collective action presents a potential channel for addressing such bottlenecks in the supply chain but favourable policies must be geared towards smallholder agriculture in order to ensure successful collective action. This paper investigates the role of collective action in smallholder market participation using a sample of 150 sweet potatoes producing households in Southwest Kenya. Our findings suggest that market participation is predominantly determined by the resource base of a household whereby, size of land owned is a fundamental factor. Furthermore, the results provide supportive evidence that participation in collective action has the potential to strengthen market participation among the poor and marginalized smallholder producers.