The High School National Championship Tournament (HSNCT) is a premier national tournament run by NAQT every May, typically over Memorial Day weekend. The tournament is a two-day affair, with preliminary rounds Saturday and playoff rounds Sunday. There are also optional scrimmage rounds on the Friday before.
The HSNCT currently draws the largest field of any national tournament. In 2017 it attracted 304 high school teams from 235 different schools. The most common way to qualify for the HSNCT is to finish in the top 15% at a tournament using NAQT questions during the season, though there are some other ways.
Recent HSNCT tournament sets have contained 26 or 27 packets, each of 24 tossups and 24 bonuses. The first two HSNCTs used NAQT's second-generation format of 28 tossups and 26 bonuses, with the possibility of tossups being read for tossup points only and no bonus potential if the end of the packet was reached. From 2001 to 2010, the packets had 26 tossups and 26 bonuses each.
The 2009 HSNCT was the last to use math calculation tossups; since 2010, these have been removed from the distribution. Most HSNCT packets now contain exactly one computation bonus (and never more than one). Packets also contain non-computational math questions.
In 2018 a new tournament format was introduced in which teams played seven power-matched preliminary games Saturday morning or seven power-matched preliminary games Saturday afternoon (with no byes), then played three more preliminary games in six rounds (and thus had three byes) on Sunday morning, followed by double-elimination playoffs on Sunday afternoon and evening, with 6-4 teams starting in the losers' bracket and a cross-bracketed match near the end of the playoffs to accelerate the double-elimination.
From 2003 to 2017, the format was essentially ten power-matched preliminary games over more than ten rounds on Saturday (so teams had several byes), followed by double-elimination playoffs on Sunday, sometimes with 6-4 teams starting in the losers' bracket, and a cross-bracketed match near the end of the playoffs to accelerate the double-elimination.
The 1999 and 2002 tournaments used swiss-pair prelims followed by a round-robin playoff bracket. The 2000 and 2001 tournaments used pre-scheduled prelims followed by the double-elim playoffs.
From 2001 to 2013, the HSNCT also recognized a Small School Champion. Schools fitting the criteria played as part of the regular tournament Saturday and Sunday. After they were eliminated from the regular tournament, they played in a separate set of playoff rounds that determined the Small School Champion. Since 2014 NAQT's Small School championship has instead been decided at a separate event.
Most years, select matches from the HSNCT are audio-recorded. In 2011 and 2012 some rounds were video-recorded by iHigh. Since about 2017 one match in each of the last few playoff rounds has been livestreamed.