The objective of the study was to assess factors affecting market participation of agro-forestry smallholder farmers in Uganda. Primary data on household, farm and marketing characteristics were collected from 153 farming households using a semi-structured, pre-tested questionnaire. The determinants of market participation were assessed using the Probit model. Descriptive statistics showed that a combination of crop, livestock and tree products were marketed by farmers. The main products included maize, cassava and coffee (crops); firewood and poles (tree products); and birds and goats (livestock products). Results from the Probit model showed that farm size, household size, education level, access to credit and extension visits had positive and statistically significant effects on market participation of farmers in agro-forestry products’ markets. Age of farmer had a negative and statistically significant effect on the participation. Emphasis on improving the quality and coverage of extension services, extending credit facilities to farmers and intensifying agro-forestry training among farmers are suggested as avenues to enhance participation of farmers in agro-forestry products’ markets.