Improving the productivity of smallholder farmers particularly in developing countries has taken different approaches. Contract farming is one of the approaches employed to increase farmers’ productivity. However, agricultural outcomes have not been consistent with contract farming in developing countries. Hence, we examined the effect of contract farming on productivity of cassava farmers in Iseyin Local Government Area of Oyo State, Nigeria. Primary data were collected using a multi-stage procedure to select the farmers. Descriptive and econometric methods were employed for data analysis. The findings revealed that farm size and years of education of the participants in contract farming in the area were significantly different from non-participants by 0.45 ha and 1.76 years, respectively. Years of education, farm size, planting improved cassava variety, price of cassava output and being a female cassava farmer were significant drivers of participation. The mean productivity of the cassava farmers was about 0.89. Non-participants showed a higher productivity than their counterparts in contract farming. Although farm size increased productivity of cassava farmers, household size and contract farming significantly reduced it in the area. Hence, it was concluded that contract farming does not always significantly improve agricultural outcomes. Planting high-yielding varieties coupled with best agronomic practices will better address the issue of declining productivity of the cassava farms in the area, alongside reduction in family size. Further, giving considerable attention to favourable technical supports and contract terms will improve contract farming effect on agricultural outcomes.