Behcet's disease is a rare, chronic inflammatory disorder that can affect various organs, with large vessel involvement being particularly uncommon. This case report discusses a 17‐year‐old male with Behcet's disease who presented with a rapidly enlarging, painful mass in the right groin region, later diagnosed as a femoral artery aneurysm. The patient underwent successful surgical intervention and was subsequently managed with immunosuppressive therapy to prevent relapse.