Statistics New Zealand (Māori: Tatauranga Aotearoa), branded as Stats NZ, is the public service department of New Zealand charged with the collection of statistics related to the economy, population and society of New Zealand. To this end, Stats NZ produces censuses and surveys.

The organisation's staff includes statisticians, mathematicians, computer science specialists, accountants, economists, demographers, sociologists, geographers, social psychologists, and marketers.

Stats NZ is divided into seven organisational subgroups, each managed by a Deputy Government Statistician:

Many of the agency's powers, duties, and responsibilities are governed by acts of the New Zealand Parliament. The agency is a state sector organisation of New Zealand operating under the authority of the Statistics Act 1975.

The department conducts the New Zealand census every five years. The census is officially done on one day. The most recent released census was in 2018 (the first data from the 2023 census is due for release on 29 May 2024). The count of usual residents (excluding visitors from overseas) from the 2018 census was 4,699,755. they lived in 1,664,313 occupied dwellings; their median age was 37.4 years (half older, half younger); 775,836 identified themselves as "Māori" (16.5% of the population); people had a median income of $31,800. This is a main source of information, and data collected from this census is often used for further purposes within the department as well as serving as benchmark information for numerous reports and surveys. For example, the census asks about the main means of travel to work, but by combining this with data from transport surveys, the department can issue detailed reports such as "Commuting Patterns in New Zealand: 1996–2006", with specific inferences such as "Over half of people who walked or jogged to work lived within 2km of their workplace." This information is helpful for business purposes, government decision-making, media purposes, foreign policy, journalism, public information, planning, and for many other uses. For example, the Federal Reserve Bank of New Zealand uses statistics from this agency about prices and wages to help develop economic indicators, exchange rate information, and the official cash rate.

The department supplies a wide variety of information. It reports on labour costs, incomes, civil unions and marriages, employment, electronic card transactions, food prices, retail trade, births and deaths, prices of capital goods, overseas trade, screen industry, international visitor arrivals, overseas merchandise, agriculture and fish stocks, water resources, building consents, electronic card transactions, English language providers, wholesale trade, local authority information, balance of payments data, manufacturing surveys, commuting patterns, mapping trends, culture and identity statistics, housing trends, work stoppages, gross domestic product, industrial energy use, and the list goes on and on. In addition, it analyses trends and publishes forecasts. The agency does not involve itself with political polling generally.

The agency provides information to the public. Many surveys and reports are available free of charge on its website; users can download spreadsheets electronically. In addition, some private market research firms use the agency's vast database information as source material, combining it with value-added presentation software (such as sophisticated mapping programmes), and then sell the re-packaged information.

Information from demographers is used as source material by journalists for articles. Sometimes statistics can influence public policy. For example, Stats NZ demographers in 2008 spotted a trend of fewer women having children and wrote: "Deciding not to have children happens as a consequence of other life events.... Education, career, mortgages, changes in family and partners for many couples, childlessness is what happens while they are making other plans." Their report was picked up by journalists at the Sunday Star-Times to form the basis of an article with the headline "New Zealand women stop having babies". The article discussed ramifications, such as possible workforce shortages and increased cost of elderly care, as well as possible policy actions such as a "Working for Families" programme. Newspaper headlines can influence public opinion which may impact policy decisions. Stats NZ information is used by government to explore tough problems; a research paper dated April 2009 used agency statistics when exploring how to handle gang violence.