Jack Oosterlaak

Justus Kinloch Ayres Oosterlaak also known as Jack Oosterlaak (15 January 1896, in Wellington – 5 June 1968), was a South African athlete who competed mainly in the 400 metres.

He competed for South Africa in the 1920 Summer Olympics held in Antwerp, Belgium in the 4 x 400-metre relay where he won the silver medal with his teammates Harry Davel, Clarence Oldfield and Bevil Rudd.