Spin bowling, sometimes known as slow bowling, is a technique used for bowling in the sport of cricket. Practitioners are known as spinners or spin bowlers.

The main aim of spin bowling is to bowl the cricket ball with rapid rotation so that when it bounces on the pitch it will deviate, thus making it difficult for the batsman to hit the ball cleanly. The speed the ball travels is not critical, and is significantly lower than for fast bowling. A typical spin delivery has a speed in the range 70-90 km/h (45-55 mph).

Spin bowling is divided into four different categories, depending on the particular physical technique used. There is virtually no overlap between the two basic biomechanical techniques of wrist spin and finger spin.

Off spin - Right-handed with finger spin technique.
Leg spin - Right-handed with wrist spin technique.
Left-arm orthodox spin - Left-handed with finger spin technique.
Left-arm unorthodox spin - Left-handed with wrist spin technique.
Depending on technique, a spin bowler uses wrist or finger motion to impart spin to the ball around a horizontal axis that is at an oblique angle to the length of the pitch. This sort of spin means it is also possible for the Magnus effect to cause the ball to deviate sideways through the air, before it bounces. Such deviation is called drift. The combination of drift and spin can make the ball's trajectory complex, with a change of direction at the bounce.

The variety of trajectories achievable by a spin bowler can bewilder inexperienced or poor batsmen, and most players consider them to be the most difficult style of bowler to bat against.

Spin bowlers are generally given the task of bowling with an old, worn cricket ball. A new cricket ball better suits the techniques of fast bowling than spin bowling, while a worn one grips the pitch better and achieves greater spin. Spin bowlers are also more effective later in a game, as the pitch dries up and begins to crack and crumble. This again provides more purchase for the spinning ball and produces greater deviation.