A prospective longitudinal design was employed to ascertain whether different types of behavioral inhibition (i.e., traditional, peer-social) were stable from toddler to preschool age, and whether inhibited temperament and/or parenting style would predict children's subsequent social and behavioral problems. At Time 1, 108 toddlers (54 males, 54 females) and their mothers were observed in the Traditional Inhibition Paradigm and in a toddler-peer session; then at age 4 years, 88 children were observed with unfamiliar peers, and maternal ratings of psychological functioning were obtained. How mothers and their toddlers interacted was also observed. Results revealed meaningful connections between toddler inhibition, maternal intrusive control and derision, and nonsocial behaviors at age 4. Both forms of toddler inhibition predicted socially reticent behavior during free play at 4 years. If mothers demonstrated relatively high frequencies of intrusive control and/or derisive comments, then the association between their toddlers' peer inhibition and 4-year social reticence was significant and positive; whereas if mothers were neither intrusive nor derisive, then toddlers' peer inhibition and 4-year reticence were not significantly associated. Thus, maternal behaviors moderated the relation between toddlers' peer inhibition and preschoolers' social reticence.