Ecclesiastical Law is the body of law derived from canon and civil law and administered by the ecclesiastical courts.  Ecclesiastical law governs the doctrine of a specific church, usually, Anglican canon law.  Ecclesiastical law is also termed as jus ecclesisasticum or law spiritual.

Ecclesiastical courts were established to hear matters concerning the religion.  The jurisdiction exercised by ecclesiastical courts played a major role in the development of the English legal system.  Their duties and work were not limited to the controlling of clergies and doctrines of the Church.  Before the Reformation, the ecclesiastical courts had significant jurisdiction.  In matters relating to matrimonial causes and testate and intestate succession, the law remained significant and relevant until the mid of the nineteenth century.

Since ecclesiastical courts were not established in the United States, the code of laws enforced in such courts could not be considered part of the common law that existed in the colonies.  It has also been stated that the canon and civil laws administered by the ecclesiastical courts of England should be grouped along with the unwritten laws of England which were adopted and used in certain jurisdiction.  Therefore, it is argued  that such laws should be employed where the rule of the ecclesiastical courts is deemed to be better law than the rule announced by a common law court.