In professional sports, a salary cap (or wage cap) is an agreement or rule that places a limit on the amount of money that a sporting club can spend on player salaries. The limit exists as a per-player limit or a total limit for the team's roster, or both. Several sports leagues have implemented salary caps, both as a method of keeping overall costs down, and to ensure parity between teams so a wealthy team cannot entrench dominance by signing many more top players than their rivals. Salary caps can be a major issue in negotiations between league management and players' unions, and has been the focus point of several strikes by players and lockouts by owners and administrators.

Salary caps are used by the following major sports leagues around the world:

In addition, the four Welsh regional sides in rugby union's Pro 12 have unilaterally adopted a salary cap effective with the 2012–13 season.

In theory, there are two main benefits derived from salary caps - promotion of parity between teams, and control of costs.