Symptoms of psychopathology that onset during childhood are often more severe, chronic, and difficult to treat than symptoms that first appear later in life. Maternal psychological symptoms are associated with the development of psychological symptoms in children. However, less research focuses on whether children’s behaviors may presage maternal psychological difficulties that, in turn, contribute to the child’s own psychological functioning. Identifying psychological difficulties in families and intervening in early life may lower risk for intergenerational transmission of subsequent psychological symptoms. Even at non-clinical or normative levels, exploring transactional models of parent-child behavior and psychological functioning may provide insight into the development of later psychological difficulties or symptoms within families. Thus, the current study examined whether difficult infant behavior (e.g., fussiness, unpredictability) is associated with future maternal psychological difficulties and subsequently, the child’s own psychological functioning in early childhood. The current sample includes 847 dyads from a multi-wave birth cohort in England (‘Born in Bradford’), who identified as predominantly non-White (62.2%) and socioeconomically diverse. Mothers reported on their child’s behaviors at 6 months, their own psychological functioning during pregnancy and at 18 months postpartum, and their child’s psychological functioning at age 3. Results of a mediation model revealed that the association between infant behavior at 6 months and child psychological functioning at 3 years is partially explained by maternal psychological functioning at 18 months, even after accounting for psychological difficulties during pregnancy, maternal age at birth, child sex, family income, and ethnicity. Post-hoc exploratory analyses revealed that the association between infant behavior, maternal psychological functioning, and subsequent child psychological functioning was significant for Pakistani British families but not White British families. These findings provide preliminary evidence that infant behaviors (e.g., temperament) may presage future maternal psychological difficulties and subsequent child psychological functioning, above and beyond previous maternal psychological functioning. Importantly, these results highlight infant behavior as a potential catalyst for later psychological difficulties within families.