The study examined the impact of off-farm work adoption on productivity-enhancing inputs (fertilizer and herbicide) in Southwest, Nigeria. Treatment effects model which addresses selection bias issue while considering observed and unobserved factors was used in the analysis of the data collected from sampled respondents. Endogenous Switching Regression (ESR) Model was also employed for the purpose of carrying out a robustness check. Empirical findings from the study showed that years of formal education and membership of cooperative society increased the likelihood of adopting off-farm work. Also, the study confirmed the positive role of extension services in investing in productivity-enhancing inputs as number of extension visits increased level of fertilizer expenditure in the study area. Furthermore, the study clearly showed that off-farm work adoption had direct and significant impact on both fertilizer and herbicide expenditures with the marginal effects of 6.1300 and 3.1023, respectively. Therefore, policies that promote off-farm work adoption should be put in place by all the concerned authorities in the study area. The findings that emanate from this research exercise give valuable supports to the policy architects in coming up with social and agri-environmental policies. Manuscript profile