The Master of Laws is an advanced academic degree, pursued by those holding a professional law degree, and is commonly abbreviated LL.M. (also LLM) from its Latin name, Legum Magister, where the double L stands for the Latin plural, because both profane and ecclesiastical law are included. (For female students, the less common variant Legum Magistra may also be used.) The University of Oxford names its taught masters of laws B.C.L. (Bachelor of Civil Law) and MJur (Magister Juris), while the research masters is named either MPhil (Master of Philosophy) or MSt (Master of Studies).

To become a lawyer and practice law in most states and countries, a person must first obtain a law degree. While in most common law countries a Bachelor of Laws (or LL.B.) is required, the U.S. requires a professional doctorate, or Juris Doctor, to practice law.

If a person wishes to gain specialized knowledge through research in a particular area of law, he or she can continue his or her studies after an LL.B or J.D. in an LL.M. program. The word legum is the genitive plural form of the Latin word lex and means "of the laws". When used in the plural, it signifies a specific body of laws, as opposed to the general collective concept embodied in the word jus, from which the words "juris" and "justice" derive.