The law of New Zealand uses the English common law system, inherited from being a part of the British Empire.

In New Zealand law and politics, the principles of the Treaty of Waitangi is a phrase used in the Treaty of Waitangi Act 1975. It is a set of principles derived from, and interpreting, the Treaty of Waitangi. These principles were codified in 1987, partly an attempt to reconcile the different Māori and English language versions of the treaty, and allow the application of the treaty to a contemporary context.