.au Domain Administration (auDA) is the manager of the .au domain, which is the country-code top-level domain for Australia. It is a not-for-profit organisation, whose membership is open to organisations or individuals who have an interest in Australian domain name matters.

The operation of .au began with Robert Elz of Melbourne University. He devised the original policies, and was responsible for the day-to-day operation of the domain. All services were provided free.

In 1996, the operation of the popular .com.au sub-domain became too much for him to accomplish on a voluntary basis. He decided to give its operation exclusively to the commercial arm of the university Melbourne IT for a term of five years.

The service was run on a for-profit basis. Many also argued that Melbourne IT had no right to charge for services that had been previously provided free, ultimately resulting in a class-action lawsuit filed by ISP iiNet on behalf of all domain holders.

Disenchantment in the way .au was run also grew when times taken to process registrations or updates to domain names in other areas (such as .org.au) ballooned to months or even years. For these and other reasons, Robert Elz lost control of the .au namespace to auDA on December 12, 2001