INTRODUCTION: This review aims to present the current state of knowledge about attachment and obsessive-compulsive disorder (OCD), the connection to the disorder's course, and the treatment effectiveness. METHOD: A literature search was performed using PubMed, Google Scholar, Web of Science, and ScienceDirect databases using the following search terms: obsessive compulsive disorder, attachment, therapy, treatment, and long-term outcome. The period of extraction was between January 1990 and October 2020. RESULTS: Insecure attachment leads to the formation of dysfunctional beliefs about the world and self, which influences the dynamics of OCD. It is associated with maladaptive cognitive processes such as an inflated sense of responsibility, perfectionism, and mind control. With worse emotional regulation and reduced self-esteem (which can also result from insecure attachment), it can lead to maladaptive behaviour such as perfectionistic and compulsive behaviour to secure and stabilize self-worth and safety. Of the two dimensions that define insecure adulthood attachment (anxiety and avoidance), attachment anxiety is more closely related to OCD. While anxious attachment can lead to a worse response in acute treatment, secure attachment is a protective factor that can improve remission. CONCLUSIONS: Anxious attachment is common in patients with OCD and interconnects with primary OCD symptomatology. From this perspective, strategies that promote feelings of safety, acceptance, and appreciation within a therapeutic relationship may be essential in treating OCD.