A facile metal-free graphene oxide (GO)-catalyzed synthesis of tosylaziridines using PhINTs as the nitrene source is reported. The reaction involves nitrene insertion into a variety of styrene/nitrostyrene derivatives in the presence of iodine at room temperature and in water. The envisaged process is highly green, operationally simple, it employs metal-free catalysis and it affords excellent yields (85–92%) and high diastereoselectivity (95–98%) of the Z-isomer of the product. The catalyst used could be recycled for further use in other reactions.