This study examines the technical, allocative, and economic efficiencies of the cotton-wheat farming system in Punjab, Pakistan. It also investigates the determinants of these efficiencies using a non-parametric data envelopment analysis (DEA) technique. Technical, allocative, and economic inefficiency scores are separately regressed on socioeconomic and farm-specific variables to identify the sources of inefficiency using a Tobit regression model. The mean technical, allocative, and economic efficiencies calculated for the system were 0.87, 0.44, and 0.37, respectively. Our results indicate that years of schooling and the number of contacts with extension agents have a negative impact on the inefficiency of cotton-wheat farming in Punjab.