A memorandum of understanding (MoU) is a document describing a bilateral or multilateral agreement between parties. It expresses a convergence of will between the parties, indicating an intended common line of action. It is often used in cases where parties either do not imply a legal commitment or in situations where the parties cannot create a legally enforceable agreement. It is a more formal alternative to a gentlemen's agreement.
In some cases depending on the exact wording, MoUs can have the binding power of a contract; as a matter of law, contracts do not need to be labeled as such to be legally binding. Whether or not a document constitutes a binding contract depends only on the presence or absence of well-defined legal elements in the text proper of the document (the so-called "four corners"). This can include express disclaimers of legal effect, or failure of the MoU to fulfill the elements required for a valid contract (such as lack of consideration in common law jurisdictions).
In private law
In private U.S. law, MoU is a common synonym for a letter of intent. One example is the MoU between Bush and Kerry for the 2004 debates iii.
Inside a company or government agency
Many companies and governmentagencies use MoUs to define a relationship between departments, agencies or closely held companies. In the United Kingdom, such an MoU is often called a concordat. An example is the 2004 Concordat between bodies inspecting, regulating and auditing health or social care. The term is often used in the context of devolution, for example the 1999 concordat between the central Department for Environment, Food and Rural Affairs and the Scottish Environment Directorate.
In public international law
In international relations MoUs fall under the broad category of treaties and should be registered in the United Nations treaty database. In practice and in spite of the United Nations' Legal Section insistence that registration be done to avoid 'secret diplomacy,' MoUs are sometimes kept confidential. As a matter of law, the title of MoU does not necessarily mean the document is binding or not binding under international law. To determine whether or not a particular MoU is meant to be a legally binding document (i.e. a treaty), one needs to examine the intent of the parties as well as the position of the signatories (e.g. Minister of Foreign Affairs vs Minister of Environment). A careful analysis of the wording will also clarify the exact nature of the document. The International Court of Justice has provided some insight into the determination of the legal status of a document in the landmark case of Qatar v. Bahrain, 1 July 1994.
One advantage of MoUs over more formal instruments is that, because obligations under international law may be avoided, they can be put into effect in most countries without requiring parliamentary approval. Hence, MoUs are often used to modify and adapt existing treaties, in which case these MoUs have factual treaty status. The decision concerning ratification, however, is determined by the parties' internal law and depends to a large degree on the subject agreed upon. MoUs that are kept confidential (i.e. not registered with the United Nations) cannot be enforced before any UN organ, and it may be concluded that no obligations under international law have been created. As was obvious in the Qatar v. Bahrain case, disputes may arise concerning the status of the document once one of the parties seeks to enforce its provisions.
Although MoUs in the multilateral field are seldom seen, the transnational aviation agreements are actually MoUs.