Exposure to early adversity places young children at risk for behavioral, physiological, and emotional dysregulation, predisposing them to a range of long-term problematic outcomes. Attachment and Biobehavioral Catch-up (ABC) is a 10-session intervention designed to enhance children's self-regulatory capabilities by helping parents to behave in nurturing, synchronous, and non-frightening ways. The effectiveness of the intervention was assessed in a randomized clinical trial, with parents who had been referred to Child Protective Services (CPS) for allegations of maltreatment. Parent–child dyads received either the ABC intervention or a control intervention. Following the intervention, children from the ABC intervention (n = 56) expressed lower levels of negative affect during a challenging task compared to children from the control intervention (n = 61).