We examined the effects of our parent-child interaction focused bookmaking intervention with 89 families and their toddlers receiving early intervention services. Participating early intervention providers (N = 24) were assigned to either continue providing services as usual or participate in training to implement the bookmaking approach in their home visits. Compared with those receiving services as usual, the mothers in the treatment group showed greater maternal parenting self-efficacy, which in turn, predicted better child language development and fewer behavior problems. A significant interaction of treatment with maternal depression suggests that being in the treatment group reduced the association of depression with parenting self-efficacy. These findings suggest that early intervention approaches focused on parent-child interaction and other family-centered practices may be effective at increasing parenting self-efficacy, buffering against the potential deleterious effects of depression on parenting self-efficacy, and strengthening parents' confidence in their own ability to promote their children's development, resulting in gains in social-emotional and language domains.