A debtors' prison is a prison for people who are unable to pay debt. Through the mid-19th century, debtors' prisons (usually similar in form to locked workhouses) were a common way to deal with unpaid debt in places like Western Europe.^[1] Destitute persons who were unable to pay a court-ordered judgment would be incarcerated in these prisons until they had worked off their debt via labour or secured outside funds to pay the balance. The product of their labour went towards both the costs of their incarceration and their accrued debt. Increasing access and lenience throughout the history of bankruptcy law have made prison terms for unaggravated indigence illegal over most of the world.

Since the late 20th century, the term debtors' prison has also sometimes been applied by critics to criminal justice systems in which a court can sentence someone to prison over willfully unpaid criminal fees, usually following the order of a judge.^[2] For example, in some jurisdictions within the United States, people can be held in contempt of court and jailed after willful non-payment of child support, garnishments, confiscations, fines, or back taxes. Additionally, though properly served civil duties over private debts in nations such as the United States will merely result in a default judgment being rendered in absentia if the defendant willfully declines to appear by law,^[3] a substantial number of indigent debtors are legally incarcerated for the crime of failing to appear at civil debt proceedings as ordered by a judge. In this case, the crime is not indigence, but disobeying the judge's order to appear before the court.^{[4][5][6][7][8]} Critics argue that the "willful" terminology is subject to individual mens rea determination by a judge, rather than statute, and that since this presents the potential for judges to incarcerate legitimately indigent individuals, it amounts to a de facto "debtors' prison" system.

During Europe's Middle Ages, debtors, both men and women, were locked up together in a single, large cell until their families paid their debt.^[9] Debt prisoners often died of diseases contracted from other debt prisoners. Conditions included starvation and abuse from other prisoners. If the father of a family was imprisoned for debt, the family business often suffered while the mother and children fell into poverty. Unable to pay the debt, the father often remained in debtors' prison for many years. Some debt prisoners were released to become serfs or indentured servants (debt bondage) until they paid off their debt in labor.

Article 1 of Protocol 4 of the European Convention on Human Rights prohibits the imprisonment of people for breach of a contract. Turkey and the United Kingdom (due to concerns over British nationality law) have signed but never ratified Protocol 4. Greece and Switzerland have neither signed nor ratified this protocol.

France allows for contrainte par corps, now denominated contrainte judiciaire, for money owed to the State by non-insolvant debtors aged from 18 to 65; its length is limited following the amount of the debt and aims to pressure the debtor to pay his debts, consequently the owed money stays owed to the State.

In the late Middle Ages, and at the beginning of the modern era, public law was codified in Germany. This served to standardize the coercive arrest (Pressionshaft), and got rid of the many arbitrary sanctions that were not universal.^[10] In some areas (like Nürnberg) the debtor could sell or redistribute their debt.

In most of the cities, the towers and city fortifications functioned as jails. For certain sanctions there were designated prisons, hence some towers being called debtors' prison (Schuldturm). The term Schuldturm, outside of the Saxon constitution, became the catchword for public law debtor’s prison.

In the early modern era, the debtor's detainment or citizen's arrest remained valid in Germany. Sometimes it was used as a tool to compel payment, other times it was used to secure the arrest of an individual and ensure a trial against them in order to garnish wages, replevin or a form of trover. This practice was particularly disgraceful to a person’s identity, but had different rules than criminal trials. It was more similar to the modern enforcement of sentences (Strafvollzug) e.g. the debtor would be able to work off their debt for a certain number of days, graduated by how much they owed.

The North German Confederation eliminated debtors' prisons on May 29, 1868.

At present a comparable concept to debtors' prison still exists in various forms in Germany:

In England, during the eighteenth and nineteenth centuries, 10,000 people were imprisoned for debt each year.^[11] A prison term did not alleviate a person's debt, however; an inmate was typically required to repay the creditor in-full before being released.^[12] In the Kingdom of Great Britain and the later United Kingdom, debtors' prisons varied in the amount of freedom they allowed the debtor. With a little money, a debtor could pay for some freedoms; some prisons allowed inmates to conduct business and to receive visitors; others (including the Fleet and King's Bench Prisons) even allowed inmates to live a short distance outside the prison—a practice known as the 'Liberty of the Rules'—and the Fleet even tolerated clandestine 'Fleet Marriages'.

Life in these prisons, however, was far from pleasant, and the inmates were forced to pay for their keep. Samuel Byrom, son of the writer and poet John Byrom, was imprisoned for debt in the Fleet in 1725, and in 1729 he sent a petition to his old school friend, the Duke of Dorset, in which he raged against the injustices of the system. Some debtor prisoners were even less fortunate, being sent to prisons with a mixture of vicious criminals and petty criminals, and many more were confined to a single cell.

The father of the English author Charles Dickens was sent to one of these prisons (the Marshalsea), which were often described in Dickens's novels.^[13] He became an advocate for debt prison reform, and his novel Little Dorrit dealt directly with this issue.^[14]

The Debtors' Act of 1869 limited the ability of the courts to sentence debtors to prison, but it did not entirely prohibit them from doing so. Debtors who had the means to pay their debt, but did not do so, could still be incarcerated for up to six weeks, as could those who defaulted on debts to the court.^[15] Initially, there was a significant reduction in the number of debtors imprisoned following the passage of the 1869 Act. By 1870, the total number of debtors imprisoned decreased by almost 2,000, dropping from 9,759 in 1869 to 6,605 in 1870.^[16] However, by 1905 that number had increased to 11,427.^[16]

Some of London's debtors' prisons were the Coldbath Fields Prison, Fleet Prison, Giltspur Street Compter, King's Bench Prison, Marshalsea Prison, Poultry Compter, and Wood Street Counter. The most famous was the Clink prison, which had a debtor's entrance in Stoney Street. This prison gave rise to the British slang term for being incarcerated in any prison, hence "in the clink". Its location also gave rise to the term for being financially embarrassed, "stoney broke".

Ιmprisonment for debts, whether to the tax office or to a private bank, was still practiced until January 2008, when the law changed after imprisonment for unpaid taxes, as well as other debts to the government or to the social security office, was declared unconstitutional after having been practiced for 173 years; imprisonment was, however, still retained for debts to private banks. The situation regarding imprisonment (προσωποκράτηση (prosōpokrάtēsē): custody) for debts to the government is still unclear, as courts continue to have this ability for criminal acts.^[17]

The Negotiable Instruments Act, 1881, as amended, contains provisions for criminal penalties, including imprisionment, if someone defaults on a debt or a payment obligation.

Section 28A of the Securities and Exchange Board of India Act, 1992 (As amended by the Securities Laws(Amendment) Act, 2014)^[18] contains provisions for penalties, including imprisonment, for failure to pay back investors or the authorities.

In India, courts have been known to jail financial defaulters as a way to coerce them to pay back their victims or the government. For example, in the case of Subrata Roy, his bail was conditional on him paying back huge amounts to the investors or the regulators.^[19]

An eighteenth century debtors' prison is found within the Castellania in Valletta, Malta, now used as offices by the Ministry for Health. It remained in use as a prison until the nineteenth century. In line with the European Convention Act, no person is to be deprived of his liberty because of the incapability to fulfill a contractual obligation.^[20]

Debtors in the United Arab Emirates, including Dubai, are imprisoned for failing to pay their debts. This is a common practice in the country. Banks are not sympathetic to the debtors once they are in prison, so many just choose to leave the country where they can negotiate for settlements later. The practice of fleeing UAE to avoid arrest because of debt defaults is considered a viable option to customers who are unable to meet their obligations.^[21][22]

Many Colonial American jurisdictions established debtors' prisons using the same models used in Great Britain. James Wilson, a signatory to the Declaration of Independence, spent some time in a debtors' prison while still serving as an Associate Justice of the U.S. Supreme Court.^[23] Fellow signatory Robert Morris spent three years, from 1798 to 1801, in the Prune Street Debtors' Prison, Philadelphia^[24][25] Henry Lee III, better known as Henry "Light-Horse" Lee, a Revolutionary War general and father of Robert E. Lee, was imprisoned for debt between 1808 and 1809^[26] where he made use of his time by writing "Memoirs of the War".^[27]

Debtors' prisons were prevalent throughout the United States up until the mid-1800s. Economic hardships following the War of 1812 with Great Britain helped swell prison populations with simple debtors. This resulted in significant attention being given to plights of the poor and most dependent jailed under the widespread practice, possibly for the first time.^[28] Increasing disfavor over debtors' prisons along with the advent and early development of U.S. bankruptcy laws led states to begin restricting imprisonment for most civil debts.^[29] At that time growing use of the poorhouse^[30] and poor farm were also seen as institutional alternatives for debtors' prisons. The United States ostensibly eliminated the imprisonment of debtors under federal law in 1833^[31][32] leaving the practice of debtors' prisons to states.

While the United States no longer has brick and mortar debtors' prisons, or "gaols for debtors" of private debts, the term "debtor's prison" in modern times sometimes refers to the practice of imprisoning indigent criminal defendants for matters related to either a fine or a fee imposed in criminal judgments.^[8][36] To what extent a debtor will actually be prosecuted varies from state to state.^[4] This modern use of the term debtors' prison arguably has its start with precedent rulings in 1970, 1971 and 1983 by the U.S. Supreme Court,^[5][37] and passage of the Bankruptcy Reform Act of 1978.

In 1970, the Court ruled in Williams v. Illinois that extending a maximum prison term because a person is too poor to pay fines or court costs violates the right to equal protection under the Fourteenth Amendment.^[38] During 1971 in Tate v. Short, the Court found it unconstitutional to impose a fine as a sentence and then automatically convert it into "a jail term solely because the defendant is indigent and cannot forthwith pay the fine in full."^[39] And in the 1983 ruling for Bearden v. Georgia, the Court ruled that the Fourteenth Amendment bars courts from revoking probation for a failure to pay a fine without first inquiring into a person's ability to pay and considering whether there are adequate alternatives to imprisonment.^[40]

A year-long study released in 2010 of fifteen states with the highest prison populations^[41] by the Brennan Center for Justice, found that all fifteen states sampled have jurisdictions that arrest people for failing to pay debt or appear at debt-related hearings.^[31] The study identified four causes that lead to debtors' prison type arrests for debts:

In an article in The American Conservative, Michael Shindler argues that another factor responsible for debtors' prison type arrests is that "Whereas indigent defendants have a Sixth Amendment right to a court-appointed lawyer in criminal cases involving incarceration, indigent debtors in state and local courts have no one to defend them against the error and abuse that characterizes debt collection litigation." Similarly, Shindler writes, regarding explicitly illegal debtors' prison type arrests ordered by local judges,"the reason these officials engage in this sort of excessive behavior is often due to ignorance."^[50]

In a 2019 report ^[71] by the Lawyers' Committee for Civil Rights Under Law argues that debtors' prisons are likely to appear in states like Arkansas where many people live in poverty and are unable to pay fines and fees, where poor record-keeping exacerbates challenges faced by defendants and where arrest warrants and drivers license suspensions make it even harder for people to pay off court-imposed debt.

In 2014, National Public Radio (NPR) posted a report stating that there were still cases of judges imprisoning people who have not paid court fees.^[51] The American Civil Liberties Union has been challenging such policies since 2009.^[52]

In September, 2015, the town of Bowdon, Georgia made international news^[53] when a sitting municipal judge, Robert A. Diment, was surreptitiously recorded threatening defendants with jail time for traffic violations if they did not provide immediate payment.^[54] The incidents caused the Bowdon Municipal Court to be closed for a month in order to implement changes in policy.^[55]

In 1976 Article 11 of the ICCPR – International Covenant on Civil and Political Rights – came into effect stating, "No one shall be imprisoned merely on the ground of inability to fulfill a contractual obligation."

This international treaty contradicts many domestic laws of ratified states which allows for civil jail.