Although dyadic theory focuses on the impact of a mother’s mental health on her own child and the impact of a child’s mental health on their own mother, commonly used statistical approaches are incapable of distinguishing the desired within-dyad processes from between-dyad effects. Using autoregressive latent trajectory modeling with structured residuals, the current study evaluated within-dyad, bidirectional associations between maternal depressive symptoms and child behavior problems from child age 1–4.5 years among a sample of low-income, Mexican American women (N = 322, M
age = 27.8) and their children. Women reported on maternal depressive symptoms and child behavior problems during laboratory visits at child age 1, 1.5, 2, 3, and 4.5 years. Results provide novel evidence of child-driven bidirectional association between maternal depressive symptoms and child behavior problems at the within-dyad level as early as child age 1 year and within-person stability in child behavior problems emerging early in life.