Evidence status: WELL SUPPORTED — but only in some traditions
A black cat crosses your path.
Do you turn around?
Carry on?
Or decide you've just had a stroke of good luck?
The answer depends surprisingly heavily on where you grew up.
The Short Answer
The negative reputation of black cats developed from several strands of European supernatural folklore, particularly the long association between cats, witchcraft and animal familiars.
By the early-modern period, alleged witches were frequently said to possess supernatural helpers that appeared in animal form. Cats were among them, although familiars could also appear as dogs, mice, toads and other creatures.
But black cats have never been universally unlucky. British and Scottish traditions also contain strong beliefs that a black cat can signify good fortune, protection or prosperity.
What We Know
Cats are unusually well suited to supernatural folklore.
They are active at night, move quietly, have reflective eyes and can appear fiercely independent from humans even while living alongside them.
In early-modern English witchcraft beliefs, alleged witches were sometimes said to possess familiars — supernatural beings appearing in animal form and acting on their behalf.
English Heritage notes that the familiar might appear as something as small as a fly, as well as more familiar animals. Cats eventually became one of the most persistent visual forms of the idea. A surviving 1579 witchcraft pamphlet includes an illustration of a witch feeding her familiars.
Over time, popular imagery simplified that complicated folklore into an extremely durable symbol:
witch + black cat.
Once the black cat itself became associated with supernatural danger, it was not a large step from “witch's familiar” to “bad omen”.
How It Became a Habit
Superstitions survive particularly well when they can be attached to a tiny everyday event.
You do not need to attend a ritual or remember an elaborate story.
You merely need a cat to walk across the road.
Twentieth-century American folklore collections repeatedly record the belief that a black cat crossing someone's path predicts bad luck. Some versions even prescribe changing direction or walking around the block to escape the omen.
Notice how little remains of the original supernatural world.
No witch is required.
No spell.
No demon.
The cat crosses your path, and the old warning activates automatically.
The Story Everyone Tells
A simplified version says that medieval Europe simply decided black cats were evil because witches owned them.
The problem is that historical folklore is rarely so uniform.
Cats were associated with witchcraft, but familiars were not always cats, cats were not always black, and attitudes towards the animals differed significantly from one region to another.
There was no single moment when “Europe” collectively declared black cats unlucky.
The association accumulated.
What the Evidence Actually Says
The connection between animals and witchcraft is DOCUMENTED.
The use of cats in imagery surrounding witches and familiars is also documented.
The later bad-luck belief is equally real as folklore: twentieth-century archives contain numerous first-hand records of people being told that a black cat crossing their path would bring misfortune.
What we do not have is one definitive event explaining why black cats, in particular, became unlucky everywhere.
And the biggest difficulty with any universal explanation is that in some places they were believed to do precisely the opposite.
So:
DOCUMENTED: Cats became strongly associated with witchcraft and familiar spirits.
WELL SUPPORTED: Those associations helped create negative black-cat imagery.
UNKNOWN: There is no single demonstrated starting point for the crossing-your-path superstition.
DOCUMENTED: Other traditions regard black cats as lucky.
Different Elsewhere
Historic Cambridgeshire folklore treated a black cat crossing your path as good luck.
The Science Museum has preserved black-cat amulets carried by British soldiers during the First World War as charms for protection and good fortune. Its collection notes that black cats have traditionally been considered lucky in England even while being regarded negatively elsewhere in Europe.
The University of Edinburgh's School of Scottish Studies Archives likewise records Scottish informants who regarded black cats as fortunate.
This makes the black cat one of our clearest examples of a superstition changing direction completely depending on where it is told.
Same cat.
Opposite omen.
Why It Stuck
Visually, black cats are almost perfect folklore animals.
In poor light, much of the body seems to disappear while the eyes remain strikingly visible.
Combine that appearance with centuries of stories involving witches, night, magic and hidden danger and the image becomes difficult to dislodge.
The cat itself never had to do anything.
Humans supplied the story.
Related Curiosities
Why Is the Number 13 Considered Unlucky?
Why Do We Throw Salt Over Our Shoulder?
Why Does Breaking a Mirror Mean Seven Years of Bad Luck?
Why Is Walking Under a Ladder Bad Luck?
Sources & Further Reading
English Heritage — historical development of witch familiars and their animal forms.
https://production.english-heritage.org.uk/learn/histories/journey-into-witchcraft-beliefs/
Smithsonian Archives of American Art — positive and negative cultural associations surrounding black cats.
https://www.aaa.si.edu/blog/2017/10/the-good-the-bad-and-the-black-cat
Museum of Cambridge — historic Cambridgeshire tradition regarding black cats as lucky.
https://www.museumofcambridge.org.uk/2021/11/folklore-in-cambridgeshire/
Science Museum Group — surviving First World War black-cat good-luck amulets.
James T. Callow Folklore Archive — recorded American black-cat-crossing superstitions.
Last checked: 19 September 2026