A bar association is a professional body of lawyers. Some bar associations are responsible for the regulation of the legal profession in their jurisdiction; others are professional organizations dedicated to serving their members; in many cases, they are both. In many Commonwealth jurisdictions, the bar association comprises lawyers who are qualified as barristers or advocates in particular, versus solicitors. Membership in bar associations may be mandatory or optional for practicing attorneys, depending on jurisdiction.

The use of the term bar to mean "the whole body of lawyers, the legal profession" comes ultimately from English custom. In the early 16th century, a railing divided the hall in the Inns of Court, with students occupying the body of the hall and readers or benchers on the other side. Students who officially became lawyers crossed the symbolic physical barrier and were "admitted to the bar". Later, this was popularly assumed to mean the wooden railing marking off the area around the judge's seat in a courtroom, where prisoners stood for arraignment and where a barrister stood to plead. In modern courtrooms, a railing may still be in place to enclose the space which is occupied by legal counsel as well as the criminal defendants and civil litigants who have business pending before the court.