Objective: This manuscript is an overview of depression due to attachment trauma and the implications of Mentalization Based Therapy (MBT) as a prospective therapy. In this paper, we aim to discuss the concept of mentalization and share information in changing the focus beyond signs and symptoms in order to understand the etiology of the interpersonal problems arising due to depression, and be wary of deficits in individual mentalizing impairments and problems.　　Method:We searched the internet database to identify publications on depression due to attachment trauma and mentalization based treatment. Search results from PubMed, Psych INFO, Cochrane library, Wiley online library, google scholar and hand-searched references identified English language research publications, pertaining to depression due to attachment trauma and mentalization-based therapy.　　Result: This article provides a brief overview of MBT in the context of attachment trauma leading to depression, its relation to TOM, measures to determine mentalizing capacity, and current trends in MBT applied to depression. Mentalizing deficits may be a marker for depression, especially due to attachment trauma formed during early childhood and at various stages of development. Research shows lower RF scores concerning issues of loss and rejection, unrelated to symptoms or distress in depressed participants. The aim is to discuss the undermined yet complex etiology of depressioni.e. attachment trauma and mentalization-based therapy to treat, maintain stability, and prevent depression relapse.