Marek Jiras (Czech pronunciation: ['mar?k 'j?ras]) (born 18 August 1976 in Prague) is a Czech slalom canoeist who competed at the international level from 1992 to 2009.
He won a bronze medal in the C2 event at the 2000 Summer Olympics together with Tomáš Máder.
They then competed in the same event at the 2004 Summer Olympics, where they finished seventh.
Jiras and Máder also won eight medals at the ICF Canoe Slalom World Championships with six golds (C2: 1999, C2 team: 1993, 1999, 2003, 2006, 2007), a silver (C2 team: 1997) and a bronze (C2: 2002).
They won five more medals at the European Championships (1 gold, 3 silvers and 1 bronze).