A professional wrestling feud is a staged rivalry between multiple wrestlers or alliances of wrestlers. They are integrated into ongoing storylines, particularly in events which are televised. Feuds may last for months or even years or be resolved with implausible speed, perhaps during the course of a single match.

Feuds are often the result of the friction that is created between faces (the heroic figures) and heels (the malevolent, 'evil' participants). Common causes of feuds are a purported slight or insult, although they can be based on many other things, including conflicting moral codes or simple professional one-upmanship such as the pursuit of a championship. Some of the more popular feuds with audiences involve pitting former allies, particularly tag team partners, against each other. Depending on how popular and entertaining the feud may be, it is usually common practice for a feud to continue on for weeks, usually building toward a match in a supercard.

Traditionally, most promoters wanted to "protect the business" by having wrestlers act in character in public, and thus further convince the live audience that the feuding wrestlers really did hate each other and looked to outdo each other. During the days when wrestling territories were more regionally-based, some feuds lasted for years, and if the feuding wrestlers were shown to really be friends, or were associating as friends in public, it would break the illusion of their feud, and undo all the work to promote it up to that point. Throughout the years, however, the wrestling business became more open, which allowed the fans to see otherwise. An incident involving the The Kliq occurred during a World Wrestling Federation house show, in which the face pair of Shawn Michaels and Scott Hall embraced the heel pair of Kevin Nash and Triple H, thus "breaking" this illusion.

A feud ( /ˈfjuːd/), referred to in more extreme cases as a blood feud, vendetta, faida, or private war, is a long-running argument or fight between parties—often groups of people, especially families or clans. Feuds begin because one party (correctly or incorrectly) perceives itself to have been attacked, insulted or wronged by another. Intense feelings of resentment trigger the initial retribution, which causes the other party to feel equally aggrieved and vengeful. The dispute is subsequently fuelled by a long-running cycle of retaliatory violence. This continual cycle of provocation and retaliation makes it extremely difficult to end the feud peacefully. Feuds frequently involve the original parties' family members and/or associates, can last for generations and may result in extreme acts of violence. They can be interpreted as an extreme outgrowth of social relations based in family honor.

Until the early modern period, feuds were considered legitimate legal instruments and were regulated to some degree. Montenegrin culture calls this krvna osveta which means "blood revenge" which had unspoken but highly valued rules.

Professional wrestling (often shortened pro wrestling, or simply wrestling) is a mode of spectacle, combining athletics and theatrical performance. It takes the form of events, held by touring companies, which mimic a title match combat sport. The unique form of sport portrayed is fundamentally based on classical and "catch" wrestling, with modern additions of striking attacks, strength-based holds and throws, and acrobatic maneuvers; much of these derive from the influence of various international martial arts. An additional aspect of combat with improvised weaponry is sometimes included to varying degrees.

The matches have predetermined outcomes in order to heighten entertainment value, and all combative maneuvers are worked in order to lessen the chance of actual injury. These facts were once kept highly secretive but are now a widely accepted open secret. By and large, the true nature of the performance is not discussed by the performing company in order to sustain and promote the willing suspension of disbelief for the audience by maintaining an aura of verisimilitude.