Cheerleading is an activity in which the participants (called cheerleaders) cheer for their team as a form of encouragement. It can range from chanting slogans to intense physical activity. It can be performed to motivate sports teams, to entertain the audience, or for competition. Cheerleading routines typically range anywhere from one to three minutes, and contain components of tumbling, dance, jumps, cheers, and stunting.

Modern cheerleading is very closely associated with American football and basketball. Sports such as association football (soccer), ice hockey, volleyball, baseball, and wrestling will sometimes sponsor cheerleading squads. The ICC Twenty20 Cricket World Cup in South Africa in 2007 was the first international cricket event to have cheerleaders. The Florida Marlins were the first Major League Baseball team to have a cheerleading team.

Cheerleading originated as an all-male activity in the United States, and remains predominantly in America, with an estimated 3.85 million participants as of 2017. The global presentation of cheerleading was led by the 1997 broadcast of ESPN's International cheerleading competition, and the worldwide release of the 2000 film Bring It On. The International Cheer Union (ICU) now claims 116 member nations with an estimated 7.5 million participants worldwide. The sport has gained a lot of traction in Australia, Canada, Mexico, China, Colombia, Finland, France, Germany, Japan, the Netherlands, New Zealand, and the United Kingdom with popularity continuing to grow as sport leaders pursue Olympic status.

Cheerleading carries the highest rate of catastrophic injuries to female athletes in sports, with most injuries associated with stunting, also known as pyramids.