Attachment Trauma (AT) is a known clinical heuristic in Psychology. However, different perspectives on it have emerged, leading to heterogeneity and confusion. In pursuit of clarity, this paper aims to navigate the perspectives surrounding AT through an integrative review. The review identifies six distinct lines of research. The initial three, falling under the attachment research tradition, include 1. Infant disorganized attachment, 2. Unresolved/disorganized adult states of mind, and 3. Adult fearful attachment in personality Psychology. The subsequent three, falling under the trauma research tradition, encompass 4. Complex Post Traumatic Stress Disorder (cPTSD), 5. Early adverse experiences, and the 6. Biological correlates of trauma. By elucidating the commonalities and disparities between these research programs the paper underscores how they seem to converge on the core concept of AT. Ultimately, a new definition of AT is put forward: “varying and long-lasting biological, psychological, and relational consequences resulting from incomplete encoding and integration of emotionally overwhelming experiences within an attachment relationship”. The definition is explained in depth, highlighting how AT may be framed as a diverse set of adaptations, rather than a diagnosis, that may nevertheless lead to maladjustment and increased risk of psychopathology. Moreover, it is argued that the biological and evolutionary nature of the attachment bond is what distinguishes the AT concept from its alternatives (e.g.,relational trauma, betrayal trauma) in terms of solidity and explanatory power.