Jannie Claassens is a former South African rugby union player known for his tenure as a centre with Northern Transvaal and his inclusion in Springbok tours, earning Springbok number 611.

Johannes Petrus "Jannie" Claassens was born on 30 June 1969 in Welkom, Free State, South Africa. He attended Hoërskool Zeerust in the North West Province, where he began playing rugby competitively. As a schoolboy, he represented Stellaland at the 1988 Craven Week tournament, a major South African schoolboy rugby event that showcases emerging talent. Claassens’ early exposure to rugby was supported by a family background in the sport.

Claassens made his provincial debut for Northern Transvaal (later the Blue Bulls) in 1990 and remained a key centre for the team until 1998.Over his career with the union, he played 102 matches and scored 58 points. He participated in significant competitions, including the Currie Cup, with standout performances such as scoring three tries in a 53 - 8 victory over Northern Free State in 1996.His aggressive playing style and consistent midfield presence cemented his reputation in domestic rugby. A memorable incident in the 1990 Currie Cup final involved Claassens diving on Natal winger Tony Watson, affecting a crucial penalty outcome.

Claassens was selected for the World XV that toured New Zealand in 1992 to commemorate the centenary of the New Zealand Rugby Union. In 1994, he was awarded Springbok number 611, joining the South Africa national squad. He toured with the Springboks to New Zealand and to Britain and Ireland. Though Claassens did not play in official test matches, he participated in eight tour matches, scoring three tries.Additionally, he represented South Africa in sevens rugby in 1993 and 1996, competing in four competitions in total.

In 1990, Claassens was voted one of South Africa Young Players of the Year, alongside notable teammates like Andrew Aitken and Theo Jansen van Rensburg. He is remembered for his powerful running style, defensive reliability, and contributions to the midfield, which influenced the performance of both Springbok and provincial teams during the 1990s.

After retiring from professional rugby at the end of the 1998 season, Claassens transitioned into private life in South Africa, with some involvement in rugby coaching at school levels and later entering the construction industry in 2010. His family continues his rugby legacy, with his son, Jannie Claassens Jr., actively playing school-level rugby and following in his father’s footsteps.