Mediation, in a broad sense, comprises an act of bringing two states, sides or parties closer or together. This article discusses the communication sense of the term. Separate articles, cultural and biological, treat of other senses of mediation.

Mediation consists of a process of alternative dispute resolution in which a (generally) neutral third party, the mediator, using appropriate techniques, assists two or more parties to help them negotiate an agreement, with concrete effects, on a matter of common interest. More generally speaking, the term mediation covers any activity in which an impartial third party (often a professional) facilitates an agreement on any matter in the common interest of the parties involved.

Mediation applies to different fields, with some common peculiar elements and some differences for each of its specialties. The main fields of mediation include commerce, legal disputes and diplomacy, but forms of mediation appear in other fields as well. Mediation in marriage technically belongs in the category, although it has followed its own peculiar history since the times of ancient Greeks: compare marriage counselling.