Objective: Bidirectional associations between child temperament (fear, frustration, positive affect, effortful control) and parenting behaviors (warmth, negativity, limit setting, scaffolding, responsiveness) were examined as predictors of preschool-age children’s adjustment problems and social competence. Method: Participants were a community sample of children (N = 306; 50% female; 64% European American) and their mothers. Observational measures of child temperament and parenting were obtained using laboratory tasks at two time points (children’s ages 36 and 54 months). Teacher-reported adjustment measures were collected at the first and third time points (children’s ages 36 and 63 months). Results: Cross-lagged analyses were performed to examine whether child temperament and parenting predict changes in one another, whether they each contribute independently to children’s adjustment, and whether these transactional relations account for adjustment outcomes. Maternal negativity at 36 months predicted increases in child frustration at 54 months. Maternal negativity and child effortful control predicted decreases in each other from 36 to 54 months. Maternal warmth predicted increases in child effortful control over time. Child frustration, child effortful control, maternal warmth, and maternal negativity at 54 months each independently predicted child adjustment problems at 63 months, controlling for problems at 36 months. Child executive control at 54 months predicted increases in child social competence at 63 months. Conclusions: The findings suggest that temperament and parenting have independent and additive effects on preschool-age child adjustment, with some support for a bidirectional relation.