Attachment insecurity in adulthood has been linked to emotion dysregulation, maladaptive relational patterns, and vulnerability to psychopathology. While several attachment-informed therapeutic models exist, few are tailored to address attachment insecurity through nonverbal, sensory-based modalities. This thesis examines the therapeutic potential of art therapy for addressing attachment insecurity in adulthood, employing philosophical inquiry to synthesize theoretical and empirical literature. Drawing on attachment theory, neurobiology, and art therapy frameworks, three core therapeutic factors are examined: sensory and tactile engagement, imagery and concretization, and therapist attunement within the triangular relationship. Findings suggest that the multisensory, embodied, and relational nature of art therapy aligns closely with the mechanisms of attachment formation and regulation, offering an alternative pathway for clients who struggle with traditional talk therapies. These therapeutic factors support emotional regulation, promote reflective functioning, and provide corrective emotional experiences, particularly for individuals who are high in attachment avoidance or have limited verbal access to emotional material. This study highlights the relevance of art therapy as an attachment-informed modality, offering a Tripartite Mechanism Model for Attachment Repair in Art Therapy, and advocating for its further integration and empirical investigation within adult mental health treatment.