This Special Issue aims to compile cutting-edge research on the neural mechanisms of obsessive-compulsive disorder (OCD), with a focus on structural/functional neuroimaging findings and emerging neuromodulation interventions. Topics include but are not limited to: MRI/fNIRS biomarkers, AI-driven imaging analysis, deep brain stimulation (DBS), transcranial magnetic stimulation (TMS), and clinical translation of these approaches. We welcome original research, reviews, and meta-analyses that bridge the gap between basic science and therapeutic innovation.