A differential susceptibility hypothesis proposes that children may differ in the degree to which parenting qualities affect aspects of child development. Infants with difficult temperaments may be more susceptible to the effects of parenting than infants with less difficult temperaments. Using latent change curve analyses to analyze data from the National Institute of Child Health and Human Development Study of Early Child Care, the current study found that temperament moderated associations between maternal parenting styles during early childhood and children's first-grade academic competence, social skills, and relationships with teachers and peers. Relations between parenting and first-grade outcomes were stronger for difficult than for less difficult infants. Infants with difficult temperaments had better adjustment than less difficult infants when parenting quality was high and poorer adjustment when parenting quality was lower.