Background: As reviewed in Chapter One, attachment interventions aim to improve caregiver-child attachment relationships by targeting insensitive and disrupted forms of caregiving behaviors. While these interventions are moderately effective at enhancing attachment security and reducing disorganization, their expected downstream impacts on children's internalizing and externalizing problems are inconsistent, revealing gaps in the literature. Thus, the aim of this dissertation was to advance the understanding of the complex relations between caregiving antecedents, caregiver-child attachment, and children’s socioemotional outcomes. Method: Chapter Two examined the combined and interactive longitudinal effects of sociodemographic risk, observed maternal disrupted caregiving, and maternal self-reported depression, psychopathology (i.e., substance use, psychosis, and posttraumatic stress), and childhood maltreatment history on observed infant attachment disorganization using longitudinal data analysis within a Canadian pregnancy cohort of 285 mother-infant dyads. Chapter Three meta-synthesized associations between observed caregiver sensitivity and children’s internalizing (k = 69) and externalizing (k = 94) problems. Sample and measurement characteristics were explored as potential moderators. Chapter Four investigated the longitudinal direct and indirect effects of observed maternal disrupted caregiving and its subdimensions on children’s internalizing and externalizing problems at 24 and 36 months in the same cohort from Chapter Two. Attachment disorganization was explored as a potential mediator of associations. Results: In Chapter Two, sociodemographic risk, maternal disrupted caregiving, and their interaction significantly predicted infant attachment disorganization. Sociodemographic risk was associated with greater attachment disorganization when disrupted caregiving was high, but not when it was low. In Chapter Three, caregiver sensitivity was significantly related to children’s internalizing and externalizing problems, with stronger associations found for externalizing problems compared to internalizing problems. Socioeconomic status, publication status, and the measure of caregiver sensitivity emerged as moderators of associations with internalizing problems. In Chapter Four, maternal disrupted caregiving and several subdimensions of disrupted caregiving were associated with infant attachment disorganization. In addition, the subdimension of maternal negative-intrusive behaviors directly predicted children’s externalizing problems at 24 and 36 months and children’s internalizing problems at 36 months. However, attachment disorganization was not related to children’s externalizing or internalizing problems, and attachment disorganization did not mediate the associations between maternal negative- intrusive behaviors and children’s behavioral outcomes. Conclusion: As discussed in Chapter Five, findings from the current studies illustrated that the associations between caregiving antecedents, caregiver-child attachment, and children's behavioral outcomes are complex. In this dissertation, caregiver sensitivity and disrupted forms of caregiving were important antecedents of attachment and socioemotional outcome in children. In addition, sociodemographic risks appeared to elucidate some of the complexities within these dynamics. Thus, by addressing insensitive and disrupted forms of caregiving, in conjunction with an integration of multifaceted approaches to mitigate the social determinants of health, practitioners and policymakers may cultivate more supportive environments for both caregivers and children, ultimately fostering improved emotional and behavioral outcomes for future generations.