A unicornuate uterus with a non-communicating rudimentary horn is a rare Müllerian duct anomaly that is frequently underdiagnosed because of its variable clinical presentation and the limitations of conventional imaging modalities. Although not considered a direct cause of infertility, it may coexist with other reproductive pathologies and contribute to adverse reproductive outcomes. Presented here is a case series of three infertile women aged 30–36 years who were diagnosed with a unicornuate uterus and non-communicating rudimentary horn during fertility evaluation. Patient A presented with primary infertility, cyclic pelvic pain, endometriosis, and bilateral tubal disease; Patient B had a seven-year history of primary infertility and was initially suspected to have unilateral tubal obstruction; and Patient C was referred with a presumed diagnosis of uterine didelphys and was subsequently found to have a unicornuate uterus with a non-communicating rudimentary horn and ipsilateral renal agenesis. In all three cases, preoperative imaging failed to establish the definitive diagnosis, which was confirmed intraoperatively through laparoscopy, chromotubation, and hysteroscopy. Patients A and B underwent laparoscopic excision of the rudimentary horn with ipsilateral salpingectomy, while Patient C underwent only ipsilateral salpingectomy. Hysteroscopic transillumination was utilized in one case to facilitate safe laparoscopic dissection and delineation of the hemiuterine anatomy. All patients had uneventful postoperative recovery and were subsequently counseled regarding fertility options. This case series highlights the diagnostic challenges posed by unicornuate uterus with a non-communicating rudimentary horn, emphasizes the importance of a high index of suspicion during infertility work-up, and demonstrates the value of minimally invasive surgical management and hysteroscopic transillumination in selected cases. Early recognition and individualized treatment may help reduce reproductive complications and improve fertility counseling and management.