Bismarck Wilhelm du Plessis (born 22 May 1984) is a South African former professional rugby union player, who played for the Bulls in the United Rugby Championship and for the Blue Bulls in the Currie Cup.

He played for the Free State Cheetahs in 2003, before moving to the Sharks in 2005 where he spent the bulk of his career, and then to Montpellier in the French Top 14.

[5] Following an illness to Pierre Spies, Bismarck du Plessis was called into South Africa's squad for the 2007 Rugby World Cup;[6] his brother Jannie was a later addition to the squad, replacing BJ Botha, who injured a knee in South Africa's final pool match against the USA.

[7] During the 2008 end-of-year Test series, the Springboks moved Smit to tighthead in order to accommodate both him and the younger, faster Du Plessis in the front row together; this change has continued through the 2009 Super 14 season and into the Boks' 2009 Test season.

At the subsequent disciplinary hearing, which was the first of his career, the judicial officer found that his action had been "careless", not deliberate, and imposed a three-week suspension, a significantly lower penalty than the three-to-six months' suspensions routinely imposed for deliberate eye-gouging.