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A defensive three-second violation, also known as illegal defense, is a basketball rules infraction in the National Basketball Association (NBA) introduced in the 2001-2002 season. It is assessed when a member of the defending team spends more than three seconds in the free throw lane (also called the key, the 16-foot lane, or "in the paint") while not actively guarding an opponent. To be considered actively guarding, a defender must be within arm's length of an opponent and in a guarding position.[1] A three-second count is suspended if:[2][clarification needed]

  • a player is in the act of shooting
  • there is a loss of team control
  • the defender is actively guarding an opponent
  • the defender clears the painted area
  • it is imminent the defender will become legal

In addition, a player guarding an opponent with the ball may be in the paint without actively guarding the opponent.[3]

The team committing a defensive three-second violation is assessed a team technical foul. The offense receives one free throw and retains possession of the ball.[4]

Prior to the 1983-1984 NBA season, any form of zone defense was considered an illegal defense violation and resulted in a warning on the first violation and then a technical foul for any subsequent violations.[5] However, the defensive three-second violation makes it difficult for NBA defenses to play zone, since zone defenses usually position a player in the middle of the key to stop penetration.[6] The Philippine Basketball Association used to follow the illegal defense rule until the 2003 PBA season when it was abolished.[7] The high school game does not use this rule, nor does European basketball.

The WNBA started using it in 2013.[8]


  1. ^ NBA Official Rules (2009-2010) Rule 10, Section VII, B. Retrieved July 25, 2010
  2. ^ NBA Official Rules (2009-2010) Rule 10, Section VII, D. Retrieved July 25, 2010
  3. ^ NBA Official Rules (2009-2010) Rule 10, Section VII, E. Retrieved July 25, 2010
  4. ^ NBA Official Rules (2009-2010) Rule 10, Section VII, Penalty. Retrieved July 25, 2010
  5. ^ Blinebury, Fran (June 8, 2006). "Rule changes have NBA back in the fast lane". Houston Chronicle. Retrieved July 26, 2010.
  6. ^
  7. ^ Cruz, Agnes (January 24, 2003). "PBA get fresh look this season". Arab News. Retrieved January 13, 2014.
  8. ^ "WNBA Announces Rules Changes for 2013 Season". WNBA. Retrieved Dec 16, 2012.