A Master of Laws (M.L. or LL.M.; Latin: Magister Legum or Legum Magister) is a postgraduate academic degree, pursued by those either holding an undergraduate academic law degree or a professional law degree.

In many jurisdictions, the LL.M. is an advanced professional degree for those already admitted to legal practice.

To become a lawyer and practice law in most jurisdictions, a person must first obtain a law degree. In most common law countries, a Bachelor of Laws (LL.B.) is required. In the United States, a bachelor's degree followed by the Juris Doctor (J.D.) [a graduate school degree], and passing an additional set of examinations (the Bar exam) is typically required to practice law.

The LL.M. program is an advanced postgraduate law program. In Canada, an LL.B is required to enter an LL.M program; in the United States and Australia, a J.D. is required. Specialized LL.M. programs have been introduced in many European countries. An LL.M. degree is typically a requirement for entry into research doctoral programs in law.

The most advanced degree programs in the law are the Doctor of Juridical Science (S.J.D. or J.S.D.), the Doctor of Philosophy (Ph.D. or DPhil) or doctorat en droit (in France), Doktor der Rechtswissenschaften (Dr. iur.) (in Germany), the Doctor of Laws (LL.D.), and the Doctor of Civil Law (D.C.L.).

Most universities offer only a small number of LL.M. programs although there is great variety over all global jurisdictions.

In Europe, LL.M. programs in European law are popular, often referred to as LL.M. Eur (Master of European Law). In the Netherlands, the title used is Meester in de Rechten (mr.) as well as in Flanders (Belgium), by those who studied Dutch or Belgian law respectively.

Some LL.M. programs, particularly in the United States and China, focus on teaching foreign lawyers the basic legal principles of the host country.