Background: Systematic reviews have shown attachment-based parenting programs to lead to improvements in parenting sensitivity and infant attachment, but none have focused specifically on the impact of attachment-based parenting programs on externalizing symptoms in young children. Objective: The objective of this study was to review published randomized controlled trial evidence regarding the impact of attachment-based early parenting interventions on externalizing behaviors in children aged 1-5 years. Methods: A systematic search of published literature available through to May 2020 was conducted. Seven published papers reporting results from trials testing six attachment-based parenting interventions were identified. Results: Three of the seven programs were shown to be associated with statistically significant improvements in child externalizing behavior (Helping Encourage Affect Regulation, Child-Parent Psychotherapy, Parent-Child Interaction Therapy--Toddlers). For one program (Child-Parent Psychotherapy), there was also evidence in one study that improvements in child externalizing behaviors were sustained at 6-month follow-up. A number of methodological limitations were present among the studies identified, most commonly reliance on parent-report measures of externalizing behavior. Conclusions: Taken together, results indicate that parenting interventions designed to promote secure parent-child attachment relationships may be effective in reducing externalizing behaviors in children aged 1-5 years of age. Further research is required to test programs in different populations and with longer follow-up times.