Abstract Background: An aneurysm of the external jugular vein is exceptionally rare. Its occurrence in children could present diagnostic challenges due to numerous potential differential diagnoses, including anomalies such as branchial cysts. Objective: This study aims to emphasize the necessity of raising suspicion for jugular venous aneurysms in children with cystic neck masses. Case Summary: We report an 18-month-old boy with a left-sided neck swelling persisting for 10 months. The swelling was cystic and increased in size during straining or crying. A preoperative diagnosis of a branchial cyst was made but was inconsistent with intraoperative findings, where a venous aneurysm was diagnosed. Ligation and excision were performed without sequelae. Conclusion: External jugular venous aneurysms, though rare, should be considered as a potential differential diagnosis in case of lateral neck swellings, especially if they demonstrate compressibility with an increase in size on Valsalva maneuvers. Simple ligation and excision are curative measures.