The lex loci delicti commissi is the Latin term for "law of the place where the delict [tort] was committed" in the conflict of laws. Conflict of laws is the branch of law regulating all lawsuits involving a "foreign" law element where a difference in result will occur depending on which laws are applied.
The term is often shortened to lex loci delicti.
When a case comes before a court and the parties and the causes of action are local, the court will apply the lex fori, the prevailing municipal law, to decide the case. However, if there are "foreign" elements to the case, the forum court may be obliged, under conflict of laws, to adjudicate whether the forum court has jurisdiction to hear the case (see forum shopping).