Saao standards for optical photometry

A review is given of the development of systems of photometric standard stars at the South African Astronomical Observatory. A brief historical perspective indicates how the Harvard E-regions were chosen as standard sequences and developed into a very precise Southern hemisphere system for UBV(RI)_c photometry. Subsequent additions of Strömgrenuvby - H and DDO photometry to samples of E-region stars and UBV(RI)_c extensions to the F-regions and the Magellanic Clouds are also described. Current programmes to extend and improve these standard stars are briefly discussed, as well as the long-standing problem of linking the Northern and Southern systems.