An oil safety cap system for jet engines includes a safety cap that fits over an oil cap and an oil fill spout. The safety cap is attached to a locking pin. The safety cap also has a first locking pin aperture that extends through the safety cap to receive the locking pin. An attachment mechanism secures the safety cap over the oil cap and the oil fill spout. The attachment mechanism includes a first clamp half removably attached to a second clamp half. The first and second clamp halves extend around the oil fill spout, beneath the safety cap. A second locking pin aperture in the second clamp half also receives the locking pin. The locking pin apertures align when the safety cap is positioned on the oil fill spout. The looking pin extends through both apertures and secures the safety cap to the attachment mechanism.