The business activity statement is a form submitted to the Australian Taxation Office by registered business entities to report their tax obligations, including goods and services tax, pay as you go withholding, pay as you go instalments, fringe benefits tax, wine equalisation tax and luxury car tax. Pay as you go withholding is sometimes known as income tax withholding, pay as you go instalments is sometimes known as income tax instalments".

The Australian Taxation Office forwards a business activity statement tailor made for each registered business entity before the end of each reporting period. It may be delivered to the business as a paper form, electronically, or via the business’s registered tax agent. Parts of the form may be pre-filled.

Related to the business activity statement is the instalment activity statement, which is used by taxpayers who are not registered for the goods and services tax, but have other tax obligations. An instalment activity statement is also used by entities that prepare a quarterly business activity statement but are required to remit their pay as you go withholding tax on a monthly basis.

The business activity statement reporting system was introduced in 2000 as a part of a major tax reform, which also included the introduction of the goods and services tax. The various forms and reporting methods have changed considerably since the initial introduction of the business activity statement.