Swing bowling is a bowling technique in cricket, in which the ball is made to curve through the air. This is in the hope that the change in the ball's flight path will deceive the batter and cause them to play the ball incorrectly. A bowler who uses this technique is called a swing bowler. Swing bowling is generally classed as a type of fast bowling.

A swing bowling delivery is either an inswinger, where the ball curves in towards the batter, or an outswinger, where the ball curves away from the batter. A swing bowler often bowls a mixture of inswingers and outswingers (as well as other non-swinging types of delivery), by changing how they hold the ball. To make the ball swing, a bowling side continually polishes one side of the ball by applying sweat to it, as well as rubbing it against their clothing to shine it, while allowing the opposite side to become gradually more rough through the course of play.

Conventional swing, also called orthodox swing, occurs when the ball is relatively new, before the shiny side becomes worn over the course of play. The airflow over the rough and shiny sides cause it to move in flight towards the rough side and away from the shiny side. Swing bowlers often use a subtly altered grip on the ball to accentuate this effect. Reverse swing is when it swings in the opposite direction - towards the shiny side. This occurs as the ball becomes more worn, and is rarer.

As swing bowling is heavily dependent on the condition of the ball, a number of ball tampering controversies have been related to it. This is where teams have allegedly tried to alter the wear of the ball illegally using materials such as sandpaper, to produce additional swing. Examples of such incidents are the 2006 ball-tampering controversy and the 2018 Australian ball-tampering scandal.

The purpose of swing bowling is to get the cricket ball to deviate sideways as it moves through the air towards or away from the batter. To do this, the bowler makes use of six factors:

Asymmetry of the ball is encouraged by the polishing of one side of the ball by members of the fielding team, while allowing the opposite side to deteriorate through wear and tear. With time, this produces a difference in the aerodynamic properties of the two sides.

Both turbulent and laminar airflow contribute to swing. Air in laminar flow separates from the surface of the ball earlier than air in turbulent flow, so that the separation point moves toward the front of the ball on the laminar side. On the turbulent flow side it remains attached longer, separating towards the rear and steering the wake to one side, generating a lift force.

Typically, a swing bowler aligns the seam and the sides of the ball to reinforce the swing effect. This can be done in two ways: