In sports strategy, running out the clock, also known as running down the clock, stonewalling, killing the clock, chewing the clock, stalling, eating clock or time-wasting (or timewasting), is the practice of a winning team allowing the clock to expire through a series of preselected plays, either to preserve a lead or hasten the end of a one-sided contest. Such measures expend time but do not otherwise have a tactical purpose. This is usually done by a team that is winning by a slim margin (or, occasionally, tied) near the end of a game, in order to reduce the time available for the opposing team to score. Generally, it is the opposite strategy of running up the score.

The process of running out the clock generally involves low-risk, low-event play, intending to minimize the ability of the other team to interfere or counter. As this produces unexciting sport for spectators, many rulebooks attempt to counteract this; some include a time limit for completing a play, such as a play clock or shot clock.

Approaches to running out the clock differ, particularly between sports. In some cases it is considered a normal aspect of the game, whereas in others it is considered unsporting. The term "time-wasting" has pejorative implications and is generally reserved for varieties of football. In other timed sports, including basketball, gridiron football, and hockey, the more neutral term "running out the clock" is more commonly used.

Time-wasting in association football consists of two forms, extending the length of stoppages when the ball is out of play, and, while the ball is in play, playing in a way as to keep possession of the ball as long as possible rather than attempting to score.

Extending the length of stoppages

A common time-wasting tactic is to make substitutions late in the game, lengthening the duration of stoppages while the change is made. Players may also feign injury, kick the ball away, obstruct the taking of a quick free kick by an opposing player, or delay the taking of their own free kicks or throw ins. If the referee considers a delay to be unreasonable, the offending player may be given a yellow card.

When playing at home, there have been some instances where teams have been accused of time-wasting by instructing (or allowing) their ball boys to delay returning the ball to the away team.

These actions should, in theory, be negated by the addition of an equal amount of stoppage time, but teams nevertheless employ these methods.