The National Federation of State High School Associations (NFHS) regulates the official rules of high school basketball. The NFHS provides a detailed rule book for coaches and players each year. Approximately 18,500 high schools follow NFHS rules in their athletic programs. The NFHS has developed high school sporting rules since it began in 1920.
The NFHS states that during the warmup period players must not enter the warmup area of the opposing team. It also states that anyone leaving the court during play for an unauthorized reason will be called for a technical foul. If players fight during the game, they will receive an automatic ejection. Players who argue with the referees and each other are subject to technical fouls and ejection.
Official high school basketball rules call for players on the home team to wear a white jersey. The number on the front must be at least 4 inches in size and the number on back at least 6 inches. Players must tuck their jerseys into their pants. Pants must remain above the hips. Only headgear for religious or medical purposes is allowed. Headbands and wristbands can be worn only if solid in color. Players may not wear jewelry.
A foul occurs when a player initiates illegal contact with a member of the opposing team. Many rules govern foul calls, and they are up to the discretion of the officials. Fouls can result in loss of possession for the team that has the ball and in free throws for the opposing team. Players are allowed four personal fouls per game. A player who commits five is disqualified for the remainder of the game.
High school basketball courts should not exceed 94 feet in length and should have a width of 50 feet; many high schools use an 84-foot court. The free-throw line is 15 feet from the backboard. The 3-point arc is 19 feet, 9 inches from the basket.
The basketball hoop has a circumference of 18 inches and sits 10 feet above the ground. The back of the hoop's rim, the area closest to the backboard, must have a gap of 6 inches from the backboard. The backboard should measure 6 feet wide and 3 1/2 feet long. High school boys use regulation-size balls with a circumference of 29.5 inches to 30 inches. High school girls use a ball size of 28.5 inches to 29 inches in circumference.
A coach may make a substitution only when a dead ball occurs or during halftime. When a substitute enters the court during a dead ball, he must stay at midcourt until the official calls him.
Each team can call three, 1-minute timeouts per game. The game consists of four, 8-minute quarters. Players have a 1-minute break between each quarter and a 10-minute break at halftime. In the case of a tie at the end of the game, teams play an extra 4-minute session without changing ends of the court.