Mariusz Siembida
Polish swimmer
Mariusz Siembida (born March 21, 1975 in Puławy, Lubelskie) is a retired backstroke swimmer from Poland, who competed for his native country at two consecutive Summer Olympics, starting in 1996 (Atlanta, Georgia).
A member of Lublinianki he is best known for winning the bronze medal at the 1997 European Swimming Championships in the men's 4×100 m medley relay, alongside Marek Krawczyk, Marcin Kaczmarek and Bartosz Kizierowski.