Ovarian torsion is a rare but serious complication of pregnancy, with an incidence of approximately 1-5: 10000 pregnancies. Here we present a case of ovarian torsion in pregnancy in a 35-year-old multigravida who presented at 16-weeks gestation with acute onset left iliac fossa pain and 1 episode of vomiting on the background of normal dating and first trimester screening ultrasounds with no ovarian abnormalities noted. On review, she was haemodynamically stable, not peritonitic, had a closed cervix on speculum exam, a fetal heart rate of 150bpm, and normal bloods. Transabdominal ultrasound revealed a single live pregnancy with a 12cm left ovarian dermoid cyst with very poor vascularity signal suggestive of ovarian torsion. She underwent an emergency laparotomy and left ovarian cystectomy with preservation of the left ovary. Histopathology confirmed a mature cystic teratoma, and tumour markers were normal. She proceeded to deliver a healthy full-term infant via elective caesarean section for breech presentation. As this case demonstrates, diagnosis of ovarian torsion can be challenging due to the non-specific clinical features, and the enlarged gravid uterus may limit ultrasound evaluation of the ovaries during obstetric ultrasounds. Ovarian torsion in pregnancy represents a surgical emergency, with prompt diagnosis and management important for maternal and fetal wellbeing, and it should be considered in the differential diagnosis of pregnant patients presenting with acute abdominal pain. Laparotomy is the most common treatment of ovarian torsion, and postoperative complications are uncommon.