Zacharias Matheus Johannes 'Gysie' Pienaar (born 21 December 1954 in Bloemfontein, South Africa) is a former South African rugby union player.
[2] He made his test debut against the visiting South American Jaguars team on 3 May 1980 as a replacement in the second half for Pierre Edwards.
His first starting cap for the Springboks was on 31 May 1980 at Newlands in Cape Town against the touring British and Irish Lions team captained by Bill Beaumont.
[3] Pienaar was capped 13 times for the Springboks, scored 2 tries and converted two penalty goals for a total of 14 test points.
Pienaar was named the SA Rugby Player of the Year for 1980.