A declaratory judgment, also called a declaration, is the legal determination of a court that resolves legal uncertainty for the litigants. It is a form of legally binding preventive by which a party involved in an actual or possible legal matter can ask a court to conclusively rule on and affirm the rights, duties, or obligations of one or more parties in a civil dispute (subject to any appeal). The declaratory judgment is generally considered a statutory remedy and not an equitable remedy in the United States, and is thus not subject to equitable requirements, though there are analogies that can be found in the remedies granted by courts of equity. A declaratory judgment does not by itself order any action by a party, or imply damages or an injunction, although it may be accompanied by one or more other remedies.

A declaratory judgment is generally distinguished from an advisory opinion because the latter does not resolve an actual case or controversy. Declaratory judgments can provide legal certainty to each party in a matter when this could resolve or assist in a disagreement. Often an early resolution of legal rights will resolve some or all of the other issues in a matter.

A declaratory judgment is typically requested when a party is threatened with a lawsuit but the lawsuit has not yet been filed; or when a party or parties believe that their rights under law and/or contract might conflict; or as part of a counterclaim to prevent further lawsuits from the same plaintiff (for example, when only a contract claim is filed, but a copyright claim might also be applicable). In some instances, a declaratory judgment is filed because the statute of limitations against a potential defendant may pass before the plaintiff incurs damage (for example, a malpractice statute applicable to a certified public accountant may be shorter than the time period the IRS has to assess a taxpayer for additional tax due to bad advice given by the CPA).

Declaratory judgments are authorized by statute in most common-law jurisdictions. In the United States, the federal government and most states enacted statutes in the 1920s and 1930s authorizing their courts to issue declaratory judgments.