The New Zealand Educational Institute (NZEI), is a professional organisation of teachers inaugurated in 1883 by the merger of district institutes of teachers, some of which had been in existence since 1864. Its importance was recognised in 1895 by the Public School Teachers' Incorporation and Court of Appeal Act. The institute and each of its branches are registered under Part VI of the Education Act of 1964. The primary object of the institute is to advance the cause of education generally, in the main by pursuing lines of policy designed to serve the best interests of the children of the country. The necessary corollary of this primary object is a reasonable remuneration for all teachers, security of tenure, leave of absence, and a just appointments system. These aims are expressed in the institute's second object: “to uphold and maintain the just claims of its members individually and collectively”.

The corporate life of the profession is organised by the institute through a closely knit structure, extending from school staff, branches, district committees, and the Dominion executive, to the annual meeting which is its supreme court, or parliament. The institute has its representatives on many sub-committees: teachers' appointments, curriculum revision, in-service training, road safety, school broadcasting, salaries, and superannuation, to mention a few.

The institute, conscious of its obligations as a professional body, has adopted a “code of ethics”. With a membership of more than 11,000, it is the largest professional organisation in New Zealand. It is the recognised mouthpiece of the primary school teachers, and it also includes in its membership a large number of teachers in post-primary schools and teachers' colleges. The institute publishes a monthly magazine National Education, and the construction of its modern seven-storey office building, Education House, at Wellington, is expected to be completed before the end of 1966.