Fan's Guide to NBA Rules and Replay Review 2026-27

The NBA Replay Center was introduced for the 2015-16 season. It is staffed on game days by at least one current NBA referee and as many as four, depending on the schedule. The Replay Center Official is one of the game officials, alongside the Crew Chief, Referee and Umpire (Rule 2 Section I). A courtside administrator at the scorer's table helps communication between the Replay Center Official, the on-court officials, the official scorer and other table personnel.

Reviews decided by the Replay Center (per NBA's Replay Center page): whether a field goal was a two- or three-point attempt, made baskets at the end of a period, out-of-bounds calls, shot clock violations on made field goals, goaltending and basket interference, clock malfunctions involving no foul or violation, 24-second shot clock resets, and the number of players on the court.

Reviews left to the on-court crew chief (per the same page): flagrant fouls, clear-path fouls, off-ball fouls, player altercations, end-of-period fouls, shot clock violations involving a foul, the correct free throw shooter, clock malfunctions involving a foul or violation, and restricted-area calls.

The 2026-27 rulebook says the Replay Center Official makes the final ruling on replays under Rule 13 except for flagrant fouls and altercations (Rule 2 Section II(h)). The Replay Center Official can also trigger some reviews immediately (Rule 13 Section I(b)). Overturns need clear and conclusive visual evidence.

Sources: https://official.nba.com/nba-replay-center/ and the 2026-27 Official NBA Playing Rules, Rule 2.

Under Rule 13 Section I, instant replay is triggered in these situations, among others:

• A field goal made with no time remaining (0:00) at the end of any period, or a foul called at 0:00.
• Officials are not reasonably certain whether a personal foul met the criteria for a flagrant foul, or for a clear-path-to-the-basket foul.
• An altercation occurs.
• A game clock malfunction at the end of a period, where officials are reasonably certain it malfunctioned.
• Uncertainty over whether a field goal was a two-point or three-point attempt, or whether a field goal or called foul came before the shot clock expired.
• Uncertainty over which player should attempt free throws.
• Uncertainty over whether an off-ball foul occurred before a shot or throw-in was released, or whether a team had the correct number of players on the court.
• In the last two minutes of the fourth period and overtimes: the rim-touch, restricted area and goaltending or basket interference reviews.

The Replay Center Official can also trigger review immediately for some two-point or three-point and shot clock questions in the first 46 minutes of regulation or first three minutes of overtime.

Source: 2026-27 Official NBA Playing Rules, Rule 13 Section I.

How many (Rule 14 Section I): each team has one challenge per game. If the first challenge is successful, the team is awarded a second.

What can be challenged: only three events:

1. A called personal foul charged to the challenging team.
2. A called out-of-bounds violation where the challenging team was not awarded possession.
3. A called goaltending or basket interference violation (not in the last two minutes of the fourth period or any overtime, where only on-court officials trigger review).

A challenge is the only way to trigger replay of out-of-bounds violations at any point in the game.

What cannot be challenged: any other call, any non-call, and for example a personal foul charged to the opponents, continuation on its own, a technical or flagrant foul, and violations such as travelling, carrying, double dribble, flopping, and offensive or defensive three seconds.

Source: 2026-27 Official NBA Playing Rules, Rule 14 Section I.

Under Rule 14 Section II, the challenging team must take these steps in sequence:

1. Call a legal timeout immediately after the call in question (unless a mandatory timeout or a timeout called by the opponents is already under way). "Immediately" means before the ball is given to the thrower-in, given to the free throw shooter, or tossed on a jump ball.
2. The head coach signals for a challenge with the instant replay signal (twirling an index finger) toward the officials, during the same interaction in which the timeout was called.
3. During that same interaction, the head coach tells the officials the specific event being challenged.

If the call came just before a mandatory timeout or an opposing team timeout, the head coach has up to 30 seconds from the start of that timeout (measured by the timeout clock) to signal and name the event.

A team loses its chance to challenge a call if it is called for delay of game after the call in question but before it calls the timeout and signals for the challenge. Once a valid challenge triggers review, the official notifies the official scorer, who records the challenge and its outcome.

Source: 2026-27 Official NBA Playing Rules, Rule 14 Section II.

Under Rule 14 Section V:

• Unsuccessful challenge: the call is not overturned and the challenging team loses its timeout.
• Successful first challenge: the team keeps its timeout (unless the timeout taken with the challenge started a mandatory timeout) and is awarded a second challenge.
• Second challenge: the team does not keep the timeout used to initiate it, even if the challenge is successful.

What counts as success:

• A challenged foul is successful only if it is overturned, meaning no foul is assigned to any player or the foul is assigned to a different player. If the foul stays on the original player, the challenge is unsuccessful, even if it is changed from a shooting foul to a non-shooting foul.
• A challenged out-of-bounds violation is successful only if the review results in possession to the challenging team, a jump ball based on clear and conclusive evidence of simultaneous last touch, or a foul proximate to the out-of-bounds violation on the opposing team with possession to the challenging team.

Source: 2026-27 Official NBA Playing Rules, Rule 14 Section V.

Standard: to overturn a challenged event, there must be clear and conclusive visual evidence that the initial call was incorrect. The result is one of two determinations: the call stands, or the call is overturned (Rule 14 Section IV(c) and (d)).

Who decides a Coach's Challenge:

• For a challenged personal foul, the on-court crew chief makes the final decision, with Replay Center personnel in a supporting role.
• For a challenged out-of-bounds violation, or a goaltending or basket interference violation, the Replay Center Official makes the final decision.
• Exception: for pre-season or regular season games conducted outside an NBA arena, the on-court crew chief decides any challenge review.

Other replays (Rule 2 Section II(h)): the Replay Center Official makes the final ruling on replays under Rule 13, except for flagrant fouls and altercations.

Source: 2026-27 Official NBA Playing Rules, Rules 2, 13 and 14.

In the last two minutes of the fourth period and of any overtime period, on-court officials can trigger replay when they are not reasonably certain about:

• Whether the ball touched the rim, so the shot clock or game clock can be adjusted.
• Whether the defender was inside or outside the restricted area on a block/charge foul where the officials have determined illegal contact occurred.
• Whether a goaltending or basket interference violation was called correctly.

In those periods a team can no longer use a Coach's Challenge for a called goaltending or basket interference violation, because review of those events is triggered only by the on-court officials.

Source: 2026-27 Official NBA Playing Rules, Rule 13 Section I(a)(10) to (12) and Rule 14 Section I(c).

• 2026-27 Official NBA Playing Rules (PDF): https://ak-static.cms.nba.com/wp-content/uploads/sites/4/2026/10/2026-27-Official-NBA-Playing-Rules.pdf
• NBA rulebook page (listing the rulebook and video rulebook): https://official.nba.com/rulebook/
• NBA Video Rulebook: https://videorulebook.nba.com/
• NBA Replay Center page: https://official.nba.com/nba-replay-center/

Instant replay is covered in Rule 13 and the Coach's Challenge in Rule 14 of the 2026-27 rulebook.