New developments in the treatment of mothers and infants affected by opioid addiction point to the promising effects of interventions that adopt a developmental perspective, occur concurrently with addiction treatment, and target the parent-infant relationship as early as possible. In this article, the authors provide general guidelines for clinicians who wish to use attachment-informed, mentalization-based approaches to support mother-child relationships during a mother's recovery from addiction. They share an update on research from "Mothering From the Inside Out (MIO)," an evidence-based individual parenting therapy developed for mothers in addiction treatment.