Kayfabe is the portrayal of staged elements within professional wrestling (such as characters, rivalries, and storylines) as legitimate or real. Although it remains primarily a wrestling term, it has evolved into a code word for maintaining the pretense of "reality" in front of an audience.

Kayfabe is often described as the suspension of disbelief essential to creating and maintaining the non-wrestling aspects of the industry, similar to other fictional entertainment; a wrestler breaking kayfabe is analogous to an actor breaking character. Since wrestling is performed in front of a live audience whose interaction with the show itself is crucial to its success, kayfabe can be compared to the fourth wall in acting, as little to no conventional fourth wall exists in wrestling to begin with.

Kayfabe was fiercely maintained for decades with the intent to deceive fans, and the lack of a conventional fourth wall often led to wrestlers being expected to maintain their characters even when living their everyday lives. With the advent of the Internet and the sports entertainment movement, the wrestling industry has become less concerned with protecting its secrets and typically maintains kayfabe only during live events and the filming of television shows. Kayfabe is even broken during shows on occasion, usually when paying tribute to deceased and retired wrestlers or when a serious injury genuinely occurs during a match.

Kayfabe is a shorthand term that involves acknowledging the staged, scripted nature of professional wrestling, as opposed to a competitive sport, despite being presented as authentic. Initially, people "in the business" (either wrestlers or those working behind the scenes) used the term kayfabe as a code among those in the wrestling profession, discussing matters in public without revealing the scripted nature. As a concept, kayfabe involves both the fact that matches are scripted and that wrestlers portray characters for their shows. Unlike actors who portray their characters only when on set or on stage, professional wrestlers often stay "in character" outside the shows, especially when interacting with fans, trying to preserve the illusion of professional wrestling. In contrast, something that is not kayfabe, be it a fight or a statement, is referred to as a "shoot".

I remember the guy who would bring our jackets back to the dressing room. Every time he did, someone would yell "Kayfabe." ... Then one night, the guy decided to stand up for himself and told the whole dressing room: "I don't mind the yelling, but I want to let you know that my name is not Kayfabe. It's Mark." ... What he didn't know is that wrestlers called people outside of the business "marks"—that's why we were yelling kayfabe in the first place.

— Pat Patterson, describing his interaction with a ring attendant in the Pacific Northwest Wrestling territory during the early 1960s.

The term kayfabe was often used as a warning to other wrestlers that someone who was not "in the know" was in the vicinity. This could include wrestlers' family members who had not been clued into the scripted nature of professional wrestling. An example of kayfabe being kept even from family members was illustrated in an article describing how in the 1970s, the wife of James Harris (known under the ring name Kamala) was celebrating that her husband had just won a $5,000 prize (equivalent to $29,000 in 2024) as he won a battle royal, not realizing that the prize money was simply a storyline or kayfabe.

The term kayfabe itself can be used in a variety of contexts, as an adjective, for instance, when referring to a "kayfabe interview", where the person being interviewed remains "in character", or when describing someone as a "kayfabe girlfriend", implying that she is playing a role, but is not actually romantically involved with that particular person. A person can also be said to be "kayfabing" someone, by presenting storylines and rivalries as real.