Legal opinion

In law, a legal opinion is in certain jurisdictions a written explanation by a judge or group of judges that accompanies an order or ruling in a case, laying out the rationale and legal principles for the ruling. In other jurisdictions, a legal opinion is not an explanation from a judge, but an opinion from a lawyer, outlining their understanding of the law.

In jurisdictions where legal opinions are prepared by judges, they usually published at the direction of the court, and to the extent, they contain pronouncements about what the law is and how it should be interpreted, they reinforce, change, establish, or overturn legal precedent. If a court decides that an opinion should be published, the opinion may be included in a volume from a series of books called law reports ('reporters' in the United States). Published opinions of courts are also collectively referred to as case law, and constitute in the common law legal systems one of the major sources of law.

In jurisdictions where a legal opinion refers to the work of a lawyer, not a judge, the opinion is usually covered by solicitor-client privilege and is not public. The lawyer provides the opinion to their client, to assist the client in deciding what course of action to take.