It is best known for its spelling reforms which are promulgated by member states, grammar books, the Green Booklet and its support of Dutch language courses and studies worldwide.

The Dutch Language Union was established by a treaty between Belgium and the Netherlands, signed on 9 September 1980 in Brussels.

It succeeded the "Cultural Agreement" (governing more than just language) between the two countries signed just after the Second World War.

The Woordenboek der Nederlandsche Taal (WNT) is a historic dictionary that includes all words used from 1500 to the present day.

The Union also supports the study of Dutch language and culture at universities and schools worldwide.

[3] The NTU has offices in The Hague and Brussels, and it comprises four institutions: The binational (Belgium and the Netherlands) Instituut voor de Nederlandse Taal ("Institute for the Dutch Language") in Leiden, formerly Instituut voor Nederlandse Lexicologie, works under the auspices of the Dutch Language Union, and is responsible for the Woordenboek der Nederlandsche Taal (Dictionary of the Dutch language).

[6] The organisation is also responsible for the external linguistic policy of the Netherlands and Flanders and is active in Indonesia and South Africa, two countries with historic links with the Dutch language.

Nevertheless, cooperation with South Africa is not limited to the Afrikaans language but aimed also at fostering multilingualism.

The Treaty on the Dutch Language Union foresees the possibility that the Kingdom of the Netherlands extends application to NTU members’ parts outside Europe.

[8] The three autonomous Caribbean countries of the Kingdom of the Netherlands, Aruba, Curaçao, and Sint Maarten, are designated as candidate member states.

[9] Additionally, Indonesia and South Africa are considered "special partners" of the Dutch Language Union.