Background: Ovarian ectopic pregnancy is a rare form of extrauterine gestation, accounting for less than 3% of all ectopic pregnancies. Its occurrence in the context of a unicornuate uterus and absent fallopian tube is exceedingly uncommon and presents a diagnostic challenge. Case Presentation: We describe a case of a 26-year-old Palestinian woman with a known right-sided unicornuate uterus who presented with acute lower abdominal pain and elevated serum ?-HCG. Transabdominal ultrasound revealed an empty uterus and a complex adnexal mass. Diagnostic laparoscopy identified a ruptured left ovarian ectopic pregnancy with massive hemoperitoneum and complete absence of the left fallopian tube. The ectopic tissue was excised laparoscopically, preserving ovarian function. Histopathology confirmed the diagnosis. The patient recovered uneventfully and was counseled regarding reproductive implications and follow-up imaging. Conclusion: This case highlights a rare combination of a unicornuate uterus, contralateral ovarian ectopic pregnancy, and absent fallopian tube. It underscores the importance of considering ectopic pregnancy even in anatomically implausible scenarios and the role of transperitoneal sperm migration. Early surgical intervention remains critical in such complex presentations to ensure fertility preservation and reduce maternal risk.