Why Is Friday the 13th Unlucky? The History Behind the Fear

Last checked: November 13, 2026, 1:10 a.m. UTC.

Friday the 13th is widely treated as an unlucky date, including in Australia, but historians have not found a single proven origin for the superstition. The strongest evidence points to two older beliefs—wariness of Friday in some Christian traditions and of the number 13 in parts of European culture—combining into a specific fear of the date in 19th-century France. The familiar story that it began with the arrest of the Knights Templar in 1307 has no known historical link to the superstition.

There is no verified new historical discovery behind the current interest in Friday the 13th. The useful takeaway is simpler: this is a cultural belief with a traceable history, not evidence that the date itself causes bad luck.

Destaques

• The Friday-the-13th superstition is not known to date from ancient or medieval times.
• Some explanations connect Friday to Christian tradition and 13 to stories such as the Last Supper, but those links are not conclusive.
• The Knights Templar were targeted on Friday, October 13, 1307, but no evidence connects that event to the superstition’s origin.
• Research has not established that Friday the 13th is inherently more dangerous than other days.

Why is Friday the 13th considered unlucky?

The short answer is that several separate traditions became attached to the same date. Friday was regarded as unlucky in some Christian contexts because it was traditionally identified as the day of Jesus’s crucifixion. The number 13 acquired negative associations in various stories and customs. Put them together, and a Friday falling on the 13th could seem doubly ominous.

These explanations should be treated as theories rather than a settled origin story. The Library of Congress’s folklife research notes that the Bible does not say Judas was the 13th guest at the Last Supper; it does not specify the order in which the guests arrived or sat. The gathering of 13 people may have helped shape the association, but the familiar detail about Judas being “number 13” is not stated in the biblical account.

Nor is Friday considered unlucky everywhere. The Library of Congress points out that the idea is tied in part to Christian traditions and is not shared across many other religions and cultures. In some Spanish-speaking countries, Tuesday the 13th is the feared date instead, showing how superstitions vary by place.

When did Friday the 13th become a superstition?

Beliefs about Friday and 13 existed separately long before historians can document the combined superstition. The Library of Congress identifies French works from 1834 as among the earliest clear references to Friday the 13th as a date associated with misfortune. Later 19th-century French plays also refer to people fearing the date. The belief then appeared in American writing and newspapers in the later 1800s.

Thomas W. Lawson’s 1907 novel Friday, the Thirteenth helped bring the phrase and idea to a wider audience. Its plot uses traders’ fear of the date as part of a story about manipulating the stock market. The book is often presented as the superstition’s starting point, but the Library of Congress notes that its characters already know the belief. That makes the novel evidence of the superstition’s popularity, not proof that Lawson invented it.

Movies later gave the date a durable horror image. The 1980 film Friday the 13th and the franchise that followed made the name familiar to audiences around the world. Popular culture has reinforced the association, but it came centuries after the older beliefs about Friday and the number 13.

Did the Knights Templar create the Friday the 13th superstition?

It is true that King Philip IV of France ordered the arrest of many Knights Templar on Friday, October 13, 1307. But a dramatic date is not the same as evidence of an origin. The Library of Congress says researchers have not found a medieval source connecting the arrests to a belief that Friday the 13th brings bad luck. The proposed link appears to be a much later explanation, not a documented chain of transmission from the 14th century.

Other popular origin stories deserve similar care. The tale that Loki arrived as the 13th guest at a dinner of Norse gods before Baldr’s death is not found in the principal medieval texts that recount the death, according to the Library of Congress’s review. And the claim that the Code of Hammurabi skipped law number 13 is misleading: the laws on the original stone were not numbered that way.

Is Friday the 13th more dangerous?

There is no sound reason to treat the date itself as a danger signal. A 1993 British Medical Journal paper suggested a possible rise in transport-related hospital admissions in a small data set, while noting that the number of cases was too small for meaningful analysis. Later research examining emergency department visits over several years did not find an overall increase in attendances on Friday the 13th. These studies have limits, but they do not support the idea that the calendar date reliably causes misfortune.

For readers in Australia, the date can be a prompt to notice how stories and habits shape expectations. If someone avoids travel, major decisions or a particular floor number because of the superstition, that choice may reflect personal comfort or custom. It does not establish that Friday the 13th changes the odds of an accident. Ordinary care—following road rules, checking plans and making decisions on evidence—remains useful on any day.

Frequently asked questions

What is the fear of Friday the 13th called?

It is often called paraskevidekatriaphobia. The term is used for fear of Friday the 13th, though most people simply describe it as a superstition or anxiety about the date.

Is Friday the 13th unlucky in every country?

No. Beliefs differ across cultures. Friday the 13th is prominent in some English-speaking countries, while Tuesday the 13th is considered unlucky in parts of the Spanish-speaking world.

Is there proof that bad luck increases on Friday the 13th?

No reliable evidence shows that the date itself causes bad luck. Research into accidents and hospital visits has not established a consistent general increase.

Sources

• Library of Congress Folklife Today, “On the Possible Origins of Friday the Thirteenth”
• ABC News Australia, “Why is there fear attached to Friday the 13th?”