Professional sports are sports in which the participants are paid for playing, as opposed to amateur athletes. Professionalism has increasingly come to the fore through a combination of developments: mass media and increased leisure have brought larger audiences, so that sports organisations or teams can command large incomes. As a result, more sportspeople can afford to make sport their primary career, and sportspeople often attain superstar, celebrity status. This can have the major advantages of increasing the level of proficiency, and boosting the popularity of certain sports. It can also be seen to exclude the part-time or amateur participant, and thus to be a limiting influence on the sport.

There have been major problems caused for some sports by either the increase of professionalism, or attempts to resist the spread of professionalism.

Professionalism has another influence through organisations seeing it as an attack on the central ethos of sport, i.e. the ethos of being done for its own sake and for pure enjoyment, rather than as a means to earning a living. Consequently, there has been some reactive resistance to professionalism in some organisations, and some people see this as having impeded the development of the sport. For example, Rugby football was seen for many years as a part-time sport engaged in by amateurs, and English cricket is alleged to have suffered in quality because of a non-professional approach.

See also list of professional sports leagues.