The principles of the Treaty of Waitangi (Māori: ngā mātāpono o te tiriti) are principles derived from both language versions of Treaty of Waitangi, signed in New Zealand in 1840. The phrase "principles of the Treaty of Waitangi" was first used in the Treaty of Waitangi Act 1975, and the principles were first expressed in mainstream law (but not codified) in 1987 after nearly a decade of development by the Waitangi Tribunal. The Tribunal was established by the Treaty of Waitangi Act, and their articulation of principles in accordance with the Tribunal's statutory role has been remarkably consistent, and principles continue to emerge and evolve rather than being static, or a code. In this way they represent a normative body of jurisprudence on western law.

The Treaty of Waitangi Act 1975 introduced the phrase "the principles of the Treaty of Waitangi". Reference to the principles occurred in the long title, the preamble, and sections 6(1) and 8(1), as it was enacted. Section 6(1) provides for the Waitangi Tribunal to inquire into claims by Māori that they are prejudicially affected by Crown acts (or omissions) that are inconsistent with the principles of the treaty. The long title of the act states:

An Act to provide for the observance, and confirmation, of the principles of the Treaty of Waitangi by establishing a Tribunal to make recommendations on claims relating to the practical application of the Treaty and to determine whether certain matters are inconsistent with the principles of the Treaty.

The text of neither te Tiriti nor the Treaty have been expressed directly in law. The texts do not have the same meaning, and while some consider that the 1840 texts "focus(es) on the issues relevant at the time it was (they were) signed", in reality the Treaty of Waitangi - the English language text - was not signed at all on 6 February 1840, and issues of Sovereignty and Governance and whenua and taonga are clearly as much issues today as they were in 1840. In the Treaty of Waitangi Act 1975 Parliament created a framework for the introduction of te Tiriti into law in a way that provided for the judiciary, rather than Parliament, to grapple with the meaning of the two texts and how those meanings might apply to real world and increasingly political circumstances. The Act requires the Waitangi Tribunal to adjudicate on whether matters brought before them were inconsistent with the principles of the Treaty. As such the principles have been developed by the Tribunal, and later by the courts. The jurisprudence of treaty principles leapt into the mainstream courts when Parliament began passing Acts referring to the principles of te Tiriti/the Treaty. Understanding and articulating those principles then became a normal matter of statutory interpretation for our courts, which is the basis of our legal system. According to some sources the principles are based loosely on these legal determinations of what were the treaty's original intentions and goals.

It is primarily elected representatitves in decision making roles and agencies of the State that are legally bound by the principles of te Tiriti/the Treaty, and the way in which the principles are applied varies in the face of the differing dimensions of the activity in question. Often, decisions and activities of State agencies are not carried in ways that reflect a compliance with te Tiriti, and these instances give rise to breaches of the principles and in some cases claims to the Tribunal. Relying on the courts to interpret te Tiriti and the treaty, and the space between them, in developing the principles has been celebrated as a legal and jurisprudential innovation unique to Aotearoa, although it is also criticised by some. The Waitangi Tribunal's key function is to evaluate Crown actions against the intentions of the parties that signed the Treaty. The Tribunal also has the specific authority to articulate the meaning of the two texts of the Treaty, within the context of Parliament's legislative scheme which requires the Tibunal to develop 'principles'. Hayward (2004) states:

The Tribunal's findings ... are expressed in the currency of treaty principles – which principles are applicable to the particular case, and how the Crown breached those principles, if at all.

In order to apply the Treaty of Waitangi in a way that is relevant both to the Crown and to Māori today, the Waitangi Tribunal and the courts must consider the broad sentiments, the intentions and the goals of the treaty, and then identify the relevant principles of the treaty on a case-by-case basis. Hayward (2004) concludes that: "... each Tribunal is required to determine the principles of each claim on a case by case basis".

Where there are issues of statutory interpretation or judicial review proceedings, the courts of New Zealand follow the case law on the principles of the Treaty originating from New Zealand Maori Council v Attorney-General. This case was brought in the High Court by the New Zealand Māori Council in 1987. There was great concern at that time about the ongoing restructuring of the New Zealand economy by the Fourth Labour Government, specifically the transfer of assets from former government departments to state-owned enterprises. Because the state-owned enterprises were essentially private firms owned by the government, there was an argument that they would prevent assets that had been given by Māori for use by the state from being returned to Māori by the Waitangi Tribunal and through treaty settlements. The Māori Council sought enforcement of section 9 of the State-Owned Enterprises Act 1986, which reads: "Nothing in this Act shall permit the Crown to act in a manner that is inconsistent with the principles of the Treaty of Waitangi". The Court of Appeal, in a judgment of its president Sir Robin Cooke, decided upon the following treaty principles: