The Lamar Hunt U.S. Open Cup, commonly known as the U.S. Open Cup (USOC), is a knockout cup competition in men's soccer in the United States of America. It is the country's oldest ongoing national soccer competition. The competition was first held during the 1913–1914 season as the National Challenge Cup, with Brooklyn Field Club winning a trophy donated by Thomas Dewar for the promotion of American soccer. It was renamed and dedicated to North American Soccer League (NASL) and Major League Soccer (MLS) executive Lamar Hunt by the United States Soccer Federation in 1999.

The United States Soccer Federation (USSF) governs most levels of soccer in the United States, including the national teams, professional leagues, and amateur leagues, being the highest soccer authority in the country. The National Collegiate Athletic Association (NCAA) governs most colleges; secondary schools are governed by state-level associations, with the National Federation of State High School Associations (NFHS) setting the rules at that level. The match regulations are generally the same between the three governing bodies although there are many subtle differences.