A private bill is a proposal for a law that would apply to a particular individual or group of individuals, or corporate entity. This is unlike public bills which apply to everyone within their jurisdiction. Private law can afford relief from another law, grant a unique benefit or powers not available under the general law, or relieve someone from legal responsibility for some allegedly wrongful act. There are many examples of such private law in democratic countries, although its use has changed over time. A private bill is not to be confused with a private member's bill, which is a bill introduced by a "private member" of the legislature rather than by the ministry.
There are two types of private Act in the United Kingdom. The first are acts for the benefit of individuals (known as private or personal acts) which have historically often dealt with divorces or granting British nationality to foreigners, but in modern terms are generally limited to authorising marriages which would otherwise not be legal.
In the United States, private bills were previously common. Now federal agencies are able to deal with most of the issues that were previously dealt with under private bills as these agencies have been granted sufficient discretion by the United States Congress to deal with exceptions to the general legislative scheme of various laws. The kinds of private bills that are still introduced include grants of citizenship to individuals who are otherwise ineligible for normal visa processing; alleviation of tax liabilities; armed services decorations and veteran benefits.
In some cases, where the recipient of a benefit of a private bill did not want it identified as such (especially in the case of tax relief), a public law would be proposed, but restricted to a certain class of persons usually identified by being in a specific location, having a specific kind of tax event, and occurring during a narrow window of time. For example, if Acme Corporation were incorporated in the (fictional) State of Winnemac on January 14, 1967, and wanted relief from a tax on the sale of a subsidiary in the City of Zenith for $18 million in stock, that occurred on April 5, 2012, their Member of Congress might write a statute declaring "such tax of the type shall not be imposed on any corporation chartered in the State of Winnemac after January 12, 1967 and on or before January 14, 1967 for an intrastate transaction involving a stock transfer of not less than $12 million nor more than $20 million which occurred after April 2, 2001 and on or before April 5, 2012." By making the terms of the law apply to only one organization it has the effect of a private law without actually naming the party to be granted relief.
In 2012, a Nigerian student, Sopuruchi "Victor" Chukwueke, became the first person in two years to be the beneficiary of a private bill . He was in the United States on an expired visa, and the bill, sponsored by Senator Carl Levin, made possible a path to permanent residency, something the University of Toledo in Ohio required for Chukwueke to be admitted to its medical school.
Private laws are published individually as slip laws and included chronologically in United States Statutes at Large. Slip laws and U.S. Statutes at Large are available in most academic libraries and Federal Depository Library Program institutions, and at the U.S. Government Printing Office. In the United States Constitution, the concept of a private law, when applied punitively, is covered by the term bill of attainder. Such punitive private laws are therefore unconstitutional. 
- Private member's bill
- List of beneficiaries of immigration/nationality-related United States Private Bills/Laws
- Hybrid bill
- Chronological Table of the Private and Personal Acts Part 33 (1910-1987), Office of Public Sector Information – retrieved 23 May 2009
- Chronological Tables of Local Acts Part 187 (1989-2003), Office of Public Sector Information – retrieved May 23, 2009
- Jesse, David. "Bill puts Nigerian closer to medical school dream". USA TODAY. Retrieved 24 January 2017.
- "For The Relief of Sopuruchi "Victor" Chukwueke (Page: S5412". Library of Congress. July 25, 2012. Retrieved 2012-12-29.
- Karimi, Faith (December 29, 2012). "Obama signs bill to grant Nigerian student U.S. permanent residency". CNN. Retrieved 2012-12-29.
- Federal Depository Libraries
- United States Constitution, Article I, Sections 9 & 10
- List of recent beneficiaries of immigration-related private bills
- United States: Beth, Richard S. (July 21, 1998). "Private Bills: Procedure in the House". house.gov. Archived from the original on 2008-05-21.
- Canada: Table of Private Acts (1867 to December 31, 2013)