A contract is a legally binding document that recognizes and governs the rights and duties of the parties to the agreement. A contract is legally enforceable because it meets the requirements and approval of the law. A contract typically involves the exchange of goods, service, money, or promise of any of those. "Breach of contract", means that the law will have to award the injured party either the access to legal remedies such as damages or cancellation.

In the Anglo-American common law, formation of a contract generally requires an offer, acceptance, consideration, and mutual intent to be bound. Each party must be those who are binding by the contract. Although most oral contracts are binding, some types of contracts may require formalities such as being in writing or by deed.

In the civil law tradition, contract law is a branch of the law of obligations.

Each country recognized by private international law has its own national system of law to govern contracts. Although systems of contract law might have similarities, they may contain significant differences. Accordingly, many contracts contain a choice of law clause and a jurisdiction clause. These provisions set the laws of the country which will govern the contract, and the country or other forum in which disputes will be resolved, respectively. Failing express agreement on such matters in the contract itself, countries have rules to determine the law governing the contract and the jurisdiction for disputes. For example, European Member States apply Article 4 of the Rome I Regulation to decide the law governing the contract, and the Brussels I Regulation to decide jurisdiction.