Intravenous immunoglobulin (IVIg) is often used as therapy in immune-mediated diseases and is generally considered a safe therapeutic agent. However, thrombotic complications such as myocardial infarction and deep vein thrombosis have been reported, although primarily in older adults. We describe a 13-year-old girl who received one dose of IVIg for immune thrombocytopenic purpura and developed fatal bilateral jugular venous thromboses. This is the first known case of IVIg-associated thrombosis in an adolescent and also the first report describing internal jugular vein thrombosis associated with IVIg infusion. We identify additional risks that may potentiate the agent's thrombotic risk.