AbstractSecure attachment in early childhood is important for wellbeing throughout life. Music interventions show promise for supporting early parent–child relationships; however, their effects on attachment security are unclear as few music intervention evaluations have measured attachment outcomes. This systematic literature review aimed to synthesize published empirical literature examining the effects of music interventions on relationship quality between typically developing children aged birth to 5 years old and their parents. The study aimed to: (1) establish whether music interventions were associated with changes in attachment-related outcomes; (2) identify music intervention characteristics likely to support secure attachment; and (3) elucidate processes through which music techniques may have contributed to attachment-related changes. Included interventions focused on the parent–child dyad, involved a substantial music component delivered by a music therapist or an allied health professional, and assessed and/or described relationship outcome/s. A total of 23 studies describing 15 unique interventions met criteria for inclusion and represented approximately 808–815 parent–child dyads. Mothers were the most common caregivers. All interventions demonstrated some effectiveness, including in attachment-related outcomes such as bonding, emotional co-regulation, and parental sensitivity. All interventions involved singing, suggesting it may be especially suitable for supporting parent–child attachment; other music techniques used included instrument playing and movement to music. Findings suggested that music interventions may facilitate attachment-related changes through intervening in psychological processes, including parental sensitivity, reflective functioning, and emotional co-regulation. Future research should develop music interventions aiming specifically to support attachment quality, and music intervention evaluations should use validated attachment assessments and longitudinal study designs.