Sugarcane farming remains an important economic activity for smallholder farmers in Kenya, especially in labor-intensive regions such as Uriri Sub-County, Migori County. Despite its importance, productivity levels remain significantly below potential, largely due to inefficient labor utilization. This study investigates the effect of labor input, measured in man-days per acre, on sugarcane productivity (yield in tonnes per acre). A cross-sectional survey and multistage sampling technique were used to choose a sample of 297 respondents and a semi-structured questionnaire were used to gather primary data. A multiple linear regression model was employed to estimate the relationship between labor spent on specific farm operations during planting, fertilizer application, weeding, and harvesting and average sugarcane productivity. The results of the study found out that each additional man-day per acre spent on planting was associated with a 0.40-tonne increase in sugarcane productivity (p < 0.001), while fertilizer application showed a 0.34-tonne increase in sugarcane productivity per acre (p = 0.035). Labor input on weeding had a positive effect of 0.46 tonnes per man-day increase in sugarcane productivity (p < 0.001), and harvesting demonstrated the strongest influence, with a 0.79-tonne increase in sugarcane productivity per acre (p < 0.001). The model intercept was 11.87, indicating the estimated sugarcane productivity per acre in the absence of the specified labor inputs, though such a scenario is theoretical. The model exhibited strong explanatory power, with an R² of 0.761 suggesting that approximately 76% of the variability in sugarcane productivity could be explained by the labor inputs considered. These findings confirm a significant and positive relationship between labor input and sugarcane productivity, emphasizing the need for timely and adequate labor allocation in key operations to maximize productivity. The study underscores the importance of addressing labor inefficiencies and supports policy efforts to enhance labor management strategies, promote mechanization, and mitigate labor shortages in the sugarcane sector.