Many tropical countries are experiencing massive land-use change with profound environmental and socioeconomic implications. In Indonesia, oil palm cultivation is rapidly expanding at the expense of more traditional crops – such as rubber and rice – and forest land. While environmental effects of the oil palm boom were analyzed in many studies, much less is known about social effects. Here, we analyze how oil palm cultivation by smallholder farmers is associated with nutrition through changing income and gender roles. The analysis uses panel data collected in Jambi Province, Sumatra, one of the hotspots of Indonesia's recent oil palm boom. Regression models show that oil palm cultivation is positively associated with nutrition and dietary quality. These associations are related to income gains that improve smallholders' access to nutritious foods from the market. Oil palm requires less labor than traditional crops, so a switch to oil palm could potentially free family labor for off-farm economic activities. We find that oil palm cultivation is positively associated with off-farm employment of male but not female household members, which may be related to unequal opportunities and social norms. Independent of oil palm cultivation, female off-farm employment is positively associated with nutrition, even after controlling for household income.