Ruan Pienaar (born 10 March 1984) is a retired South African professional rugby union player who played either as a scrum-half or as a fly-half for the Free State Cheetahs in the Currie Cup.

Besides being able to pass well, he can kick with both feet, and his vision and running style moved former Springbok coach Jake White to compare him with Australian fly-half Stephen Larkham.

Pienaar made his debut for the Springboks in the 2006 Tri-Nations against New Zealand and was a member of the successful 2007 World Cup squad.

However, on 20 June 2011 it was reported that Pienaar had been named in South Africa's 49-Man World Cup preliminary training squad.

[8] Pienaar would play in the Celtic League and Heineken Cup along with fellow Springboks Johann Muller, Robbie Diack, Pedrie Wannenburg and BJ Botha at the Belfast based side.

In October 2013 despite strong media reports linking him with Toulon,[10] Pienaar signed a new 3-year extension to his Ulster contract keeping him in Belfast until the end of the 2016/17 season.