In sub-saharan Africa tomato is an important vegetable crop. In order to promote tomato production in Tanzania, the government has undertaken several measures. This study sought to assess socio-economic and institutional factors that influence productivity among smallholder farmers in Musoma Municipality. Specifically the study aimed at assessing productivity of tomato; determining socio-economic factors influencing tomato productivity, and determining institutional factors that influence tomato productivity. The study adopted multistage sampling technique in the selection of wards, mitaa and the respondents. Purposive selection of six wards was done. Second stage involved the selection of two Mitaa from each Ward. Finally, ten to twelve respondents were randomly selected from each Mtaa, making a total of 135 respondents. The data were collected by using structured questionnaire. Focused group discussion and key informant interview were used to collect qualitative information related to tomato production, input availability and marketing. The findings show that tomato productivity in Musoma Municipality is higher than the estimated productivity in Tanzania but lower than the estimated productivity in Africa and very low than the estimated productivity globally. Factors such as age, marital status, labour availability, farm size, income, household size, education level and farming experience were found to highly influence tomato productivity. Moreover, extension service, access to credit and access to market show statistical significance with tomato productivity. The study suggests that there should be specific training programmes through agricultural extension services; inputs subsidization scheme should be extended to tomato farmers; credit institutions should be established; loans should be soft and mode of repayment attractive to farmers. There should be organized market networks and process capital investment credits and the government should facilitate tomato farmers on value addition to increase their incomes.