Maize is Kenya's main staple food crop and is of vital concern to agricultural policy decisions, food security and the overall development of both the agricultural sector and the economy. The general objective of this study was to investigate the socio economic constraints to smallholder maize production in Tobacco growing regions of South Nyanza. However, it was guided by the following specific objectives; to determine the effect of tobacco farming on maize production and to assess the impact of socio-economic factors on smallholder maize production. A survey research design was adopted in this study that was conducted in Migori County located in Nyanza Province of the republic of Kenya. The target population included smallholder maize farmers and other key informants.The study adopted both primary and secondary data that was parametrically analyzed using Statistical Package for Social Scientist (SPSS) and E-views respectively giving descriptive statistics and inferential statistics. A fitted Cobb-Douglas production model was adopted in this study and using the framework of error correction mechanism, it was found that the lagged capital input, fertilizers, labor,among others.