This article analyzes the efficiency of the intra-household allocation of female and male labor inputs in agricultural production. In a collective household model, spouses’ optimal on-farm labor supply is such that the marginal rate of technical substitution between male and female labor is equated over different crops. Using the Uganda National Household Survey 2005/06, we test whether this condition holds by estimating production functions and controlling for endogeneity using a method proposed by Gandhi, Navarro, and Rivers (2009). We find that women are less productive than men, that there is more female labor input on low productivity parcels, and that men are relatively more productive on female-controlled plots compared with male-controlled plots. Total farm output could be higher and Pareto improvements could be possible if male labor was reallocated to female-controlled plots and/or female labor was reallocated to male-controlled plots.