The FIS Nordic World Ski Championships 2009 took place 18 February – 1 March 2009 in Liberec, Czech Republic. This was the fourth time these championships were hosted either in the Czech Republic or in Czechoslovakia, having done so at Janské Lázně (1925) and Vysoké Tatry.

The FIS Nordic World Ski Championships is a biennial Nordic skiing event organized by the International Ski Federation (FIS). The World Championships was started in 1925 for men and opened for women's participation in 1954. World Championship events include Nordic skiing's three disciplines: cross-country skiing, ski jumping, and Nordic combined. From 1924 to 1939, the World Championships were held every year, including the Winter Olympics. After World War II, the World Championships were held every four years from 1950 to 1982. Since 1985, the World Championships have been held in odd-numbered years.