<p>Isthmocele, also known as cesarean scar defect, is an increasingly recognized complication of cesarean delivery, often associated with abnormal uterine bleeding, pelvic pain, and secondary infertility. This narrative review aims to provide a comprehensive overview of the condition, including its pathogenesis, risk factors, diagnostic methods, and current treatment options. The most significant risk factor for isthmocele formation is the number of previous cesarean sections, although other contributing elements include surgical technique, uterine position, and individual wound-healing capacity. Transvaginal ultrasound is the first-line imaging modality, while magnetic resonance imaging may provide enhanced visualization in selected cases. Management depends on the severity of symptoms, residual myometrial thickness, and reproductive goals. Treatment options range from conservative medical therapy to surgical interventions via hysteroscopic, vaginal, or laparoscopic approaches. Surgical correction is particularly indicated in symptomatic women with reproductive desire and thin residual myometrium. The choice of technique should be individualized on the basis of the characteristics of the defect, the presence of coexisting pathologies, and surgical expertise. Preventive strategies focus on optimal cesarean technique, with emerging evidence supporting the importance of suture method and postoperative ultrasound monitoring. Despite increasing awareness, standardized guidelines for diagnosis and treatment are lacking. A tailored approach remains essential, considering both clinical and anatomical variables. This review summarizes the current knowledge on isthmocele and highlights the need for further research to establish evidence-based protocols for diagnosis, prevention, and treatment.</p>