Bail is a set of pre-trial restrictions that are imposed on a suspect to ensure that they will not hamper the judicial process. Bail is the conditional release of a defendant with the promise to appear in court when required. In some countries, especially the United States, bail usually implies a bail bond, a deposit of money or some form of property to the court by the suspect in return for the release from pre-trial detention. If the suspect does not return to court, the bail is forfeited and the suspect may be charged with the crime of failure to appear. If the suspect returns to make all their required appearances, bail is returned after the trial is concluded.

In other countries, such as the United Kingdom, bail is more likely to consist of a set of restrictions that the suspect will have to abide by for a set period of time. Under this usage, bail can be given both before and after charge.

For minor crimes, a defendant may be summoned to court without the need for bail, or may be released on recognizance (promising to appear in court, with no bail required) following arraignment. For serious crimes, or for suspects who are deemed likely to fail to turn up in court, they may be remanded (detained) while awaiting trial. A suspect is given bail in cases where remand is not justified but there is a need to provide an incentive for the suspect to appear in court. Bail amounts may vary depending on the type and severity of crime the suspect is accused of; practices for determining bail amounts vary.