New Zealand Sign Language (commonly abbreviated to NZSL) is one of the three official languages of New Zealand. It is a language based on vision rather than sound. Ideas are expressed through signs, facial expressions and body language. Most countries have their own national sign language. Signing is not a 'universal language'.

New Zealand Sign Language has developed naturally, over time, through being used by the deaf community in New Zealand. It is not an artificially created communication system.

Just like spoken languages, sign languages have grammatical rules for creating sentences. The rules of New Zealand Sign Language are different from the rules of English. The word order in a sentence in New Zealand Sign Language is often different to that in an English sentence. There is also not always a one-for-one correspondence between an English word and a New Zealand Sign Language sign.

From questions asked in the 2006 Census, some 7,000 - 9,000 New Zealand Sign Language users are estimated to be deaf people.

In the past, misconceptions about the nature of sign language (thought to be an inferior mode of communication and not really a language at all) led to the active prohibition of New Zealand Sign Language in New Zealand schools. This prohibition has had far-reaching consequences for many deaf people, including low academic achievement, low levels of literacy in written and spoken English, and limited career options as a result.

The recognition of New Zealand Sign Language through the New Zealand Sign Language Act 2006 is a major step forward in improving the lives of deaf people.  However, this recognition is still too recent to have had a significant impact on the many inequalities that deaf people face on a daily basis.