SDO may stand for: Science and technology Scattered disc object in the Solar System Selective door operation on trains Service Data Object protocol under the CANopen protocol Service Data Objects, allowing uniform data access Social dominance orientation, a personality trait Solar Dynamics Observatory, a NASA mission to study the Sun Spatial Data Option, late Oracle Spatial and Graph Standards Developing Organization Subdwarf O star (sdO) Intel Secure Device Onboard for IoT Other uses San Diego Opera, California, US SDO Bussum, a Dutch association football club