Jury duty or jury service is a service as a juror in a legal proceeding. Different countries have different approaches to juries: variations include the kinds of cases tried before a jury, how many jurors hear a trial, and whether the lay person is involved in a single trial or holds a paid job similar to a judge, but without legal training.

In the English model, potential jurors are generally summoned for duty, and then interviewed for their suitability to serve on the jury for a particular trial. The prosecutor and defense can dismiss potential jurors for various reasons, which can vary from one state to another, and they can have a specific number of arbitrary dismissals, or unconditional peremptory challenge, which does not require specific reasons. The judge can also dismiss potential jurors.

Some courts had been sympathetic to jurors' privacy concerns and refer to jurors by number, and conduct voir dire in camera (i.e., in private). In the United States, there have also been objections to requiring jurors to publicly give private information about themselves, such as medical conditions or whether they have used illegal drugs, even though this personal information might be relevant, for example, in a case about medical malpractice or drug trafficking.

The English model of a jury draws jurors from among the citizens. This approach is based on the traditions of English common law. This approach uses an adversarial system, and the jury is separate from the court. Generally the point of the jury is to determine whether the prosecution has proven the defendant to be guilty. The jury generally does not choose the penalty. This model is used in Australia, Canada, New Zealand, Ireland, the United Kingdom, the United States, and many former British colonies, as well as Austria and Spain.

Potential jurors in Australia are randomly selected from an electoral roll.

Jurors receive a small payment for each day of attendance. Employers are also required to pay their employees "make-up pay", that is, the usual pay the employee would have earned from working, less the jury duty payment received from the state. Under the National Employment Standards, make-up pay is required only for the first ten days of jury service; however, the laws of Victoria, Queensland and Western Australia extend the make-up pay requirement for the entire duration of the jury service.

The jury system in New South Wales is administered by the Jury Services Branch of the Office of the Sheriff of New South Wales, an office in the New South Wales Department of Attorney General and Justice, and operates in accordance with the Jury Act 1977 and Jury Amendment Act 2010. These laws detail persons who are disqualified, ineligible, or may be excused from jury service. In addition, the Jury Exemption Act 1965 and section 7, "Excuse for cause", of LRC Report 117 (2007) details other persons who can or may not serve as jurors or otherwise claim exemption.

Individuals who are blind and/or deaf may be excluded from jury service.