Obsessive-compulsive disorder (OCD) is one of the most debilitating neuropsychiatric disorders, characterized by a plethora of symptoms, predominantly, intrusive thoughts and repetitive behavior. However, an emerging body of evidence suggests that immune system dysregulation, particularly involving cytokines, plays a pivotal role in its pathogenesis. This chapter endeavors to provide a comprehensive overview of the current understanding of cytokines in OCD. The chapter first highlights the recent findings linking cytokine dysregulation to serotonergic system, glutaminergic signaling, and neuroinflammation. It elucidates the intricate interplay between cytokines and these pathways, shedding light on the potential mechanisms underlying OCD pathophysiology. The chapter explores their roles in modulating neuronal function and immune response, with a focus on how their dysregulation may contribute to OCD symptomatology and briefly touches upon the clinical implications of cytokine dysregulation in OCD and the possible mechanisms of counteracting with them. Finally, future directions for research are proposed, including the need for longitudinal studies and the development of novel immunomodulatory treatments that specifically target cytokine pathways, offering promising avenues for advancing OCD treatment strategies. Overall, this chapter highlights the intricate involvement of cytokines in the pathophysiology of OCD and their potential as targets for innovative therapeutic approaches in the management of this challenging disorder.