Rapport (ra-PORE) is a close and harmonious relationship in which the people or groups concerned are "in sync" with each other, understand each other's feelings or ideas, and communicate smoothly.

The word stems from the French verb rapporter which means literally to carry something back. In the sense of how people relate to each other means that what one person sends out the other sends back. For example, they may realize that they share similar values, beliefs, knowledge, or behaviors around politics, music or sports. This may also mean that the participants engage in reciprocal behaviors such as posture mirroring or in increased coordination in their verbal and nonverbal interactions.

There are a number of techniques that are supposed to be beneficial in building rapport such as: matching your body language (i.e., posture, gesture, etc.); indicating attentiveness through maintaining eye contact; and matching tempo, terminology, and breathing rhythm. In conversation, some verbal behaviors associated with increased rapport are the use of positivity (or, positive "face management"), sharing personal information of gradually increasing intimacy (or, "self-disclosure"), and by referring to shared interests or experiences.

Rapport has been shown to have benefits for psychotherapy and medicine, negotiation, education, and tourism, among others. In each of these cases, the rapport between members of a dyad (e.g. a teacher and student or doctor and patient) allows the participants to coordinate their actions and establish a mutually beneficial working relationship, or what is often called a "working alliance". In guided group activities (e.g., a cooking class, a wine tour and hiking group), rapport is not only dyadic and customer-employee oriented, but also customer-customer and group-oriented as customers consume and interact with each other in a group for an extended period.