Tax preparation is the process of preparing tax returns, particularly income tax returns, on behalf of a taxpayer, typically for compensation. Taxpayers may complete their own returns, either manually or with the assistance of tax preparation software and online services. Alternatively, tax preparation may be conducted by licensed professionals such as attorneys, certified public accountants (CPAs), or enrolled agents, as well as by unlicensed tax preparation businesses. Some U.S. states impose licensing requirements for individuals or entities that prepare tax returns for compensation, which may apply to federal, state, or both types of tax returns.

United States income tax laws are considered to be complicated, leading many taxpayers to seek outside assistance with taxes (53.5% of individual tax returns in 2016 were filed by paid preparers). Commercial tax preparation companies have extensively lobbied against the Internal Revenue Service (IRS) creating its own free online system of tax filing like those that exist in most other wealthy countries.

The Free File Alliance provides free tax preparation software for individuals with less than $72,000 of adjusted gross income for tax year 2020. People who make more than $72,000 can use Free File Fillable Forms, electronic versions of U.S. Internal Revenue Service (IRS) paper forms. The IRS under the Joe Biden administration introduced a free electronic tax filing system, enabling individuals to avoid buying services from commercial tax preparation companies. The Republican Party and tax preparation companies have criticized this free electronic tax filing system and sought to end it.

In 2007, the IRS estimated that there were between 900,000 and 1.2 million paid preparers.

Until 2011, the IRS did not have a requirement for national registration of paid tax return preparers in the United States. Effective January 1, 2011, new rules required the registration of almost all paid federal tax return preparers. Many of the new rules, however, were soon struck down by a federal court.

The new rules had required that some paid preparers pass a national tax law exam and undergo continuing education requirements. Persons who are certified public accountants (CPAs), attorneys or enrolled agents were required to register, but were not required to take the exam and were not subject to the continuing education requirements.

For purposes of the registration requirement, the IRS had defined a "tax return preparer" as "an individual who, for compensation, prepares all or substantially all of a federal tax return or claim for refund." Beginning in mid-2011, tax return preparers (other than CPAs, attorneys, and enrolled agents and a few others) had generally been required to take and pass a competency test to become a registered tax return preparer.

Tax return preparers who had a Preparer Tax Identification Number (PTIN) before testing was to become available were to have until December 31, 2013, to pass the competency test. New tax return preparers would have been required to pass the competency test before they could obtain a PTIN. The IRS had indicated that the new rules would have applied to all kinds of federal tax returns, including income taxes and payroll taxes. A new continuing education requirement of 15 hours per year would have been imposed on tax return preparers (except for CPAs, attorneys, enrolled agents, and a few others).