The development of maternal representations of the child during pregnancy guides a mother’s thoughts, feelings, and behavior toward her child. The association between prenatal representations, particularly those that are disrupted, and toddler social-emotional functioning is not well understood. The present study examined associations between disrupted prenatal representations and toddler social-emotional functioning and to test disrupted maternal behavior as a mediator of this association. Data were drawn from 109 women from a larger prospective longitudinal study (N=120) of women and their young children. Prenatal disrupted maternal representations were assessed using the Working Model of the Child Interview disrupted coding scheme, while disrupted maternal behavior was coded 12-months postpartum from mother-infant interactions. Mother-reported toddler social-emotional functioning was assessed at ages 12 and 24 months. Disrupted prenatal representations significantly predicted poorer toddler social-emotional functioning at 24 months, controlling for functioning at 12 months. Further, disrupted maternal behavior mediated the relation between disrupted prenatal representations and toddler social-emotional problems. Screening for disrupted representations during pregnancy is needed to facilitate referrals to early intervention and decrease the likelihood of toddler social-emotional problems.