Which sectors are mostly responsible for the low TFP of developing countries? We find that the largest sectoral TFP differences between developing countries and the United States are in equipment, construction, and food. In comparison, the sectoral TFP differences are smaller in manufactured consumption and much smaller in services. We show that our level of disaggregation allows us to reconcile the results of existing studies of sectoral productivity differences, which have focused on non– comparable two–sector decompositions of the aggregate data. We also show that our results help us shed light on various theories of aggregate TFP differences.