Home » Who’s There? The Origins of a Classic Joke

March 16, 2026Uncategorized

Who’s There? The Origins of a Classic Joke

In the late 1980s, Domino’s introduced a red-suited villain called the Noid to represent everything that could ruin yKnock knock jokes feel like they’ve always existed – but the truth is they exploded almost overnight during the 1930s and became one of the biggest joke crazes in American history. In this episode, Michael Kent explores the surprising origins of the knock knock joke, how a Broadway song helped spark the fad, why newspapers complained about them, and how the format survived nearly a century of comedy trends. Then we chat with Comedian Jonathan Burns!

Humor often follows patterns. If you look through the history of comedy, you’ll notice that many jokes rely on familiar structures. Some are riddles. Some are one-liners. Some are stories with punchlines. And some depend on a rhythm between two people speaking back and forth.

The knock knock joke belongs to that last category. It is what linguists and humor scholars call a call-and-response joke. One person delivers a line that requires a response from another person before the joke can move forward. Without that response, the punchline never arrives.

That means the joke is inherently interactive. It requires participation.

But the idea of interactive humor is far older than knock knock jokes themselves. For centuries, comedians and storytellers have relied on audience participation to create rhythm and expectation. Medieval jesters sometimes used repeated questions and answers to set up punchlines. Later, theatrical comedy in Europe often relied on characters exchanging quick, rhythmic dialogue that built toward a joke.

One moment that humor historians sometimes point to appears in William Shakespeare’s Macbeth. In Act 2 of the play, shortly after King Duncan is murdered, there is a scene involving a drunken porter who hears someone knocking at the castle gate. As he stumbles toward the door, he repeatedly says variations of the phrase “Knock, knock! Who’s there?”

The lines are not knock knock jokes in the modern sense. There is no pun-based punchline waiting at the end of the exchange. But the rhythm is there. The knocking. The question. The anticipation of an answer. It is a comedic device built around the act of someone at a door asking who is on the other side.

That structure sat quietly in the background of comedy for centuries.

Then something unusual happened in the early 20th century.

Knock knock.

Who’s there?

A cultural phenomenon that nobody expected.

By the early 1930s, American entertainment was going through a period of rapid change. Radio had become a dominant form of entertainment, vaudeville was fading, and new comedic styles were emerging in film and on stage. During that time, Broadway songwriter and producer Billy Rose wrote a song in 1934 titled “Knock Knock.”

The song used a playful knocking rhythm as part of its comedic setup. It was recorded by several performers, including the popular singer and bandleader Rudy Vallée, whose radio programs reached millions of listeners across the United States. The structure of the song reinforced the rhythm of a door knock followed by a response, and audiences immediately recognized the pattern.

Within a year or two, something remarkable began happening across the country.

Children started telling knock knock jokes.

At first the jokes were simple. They relied heavily on puns and wordplay, and they followed a predictable format:

Knock knock.
Who’s there?
Name.
Name who?
Pun.

For example:

Knock knock.
Who’s there?
Lettuce.
Lettuce who?
Lettuce in, it’s cold out here.

The humor works because the phrase “lettuce in” sounds like “let us in.” Linguists refer to this kind of wordplay as phonetic reinterpretation, where a phrase is heard differently once the listener realizes how the sounds fit together.

That little trick made the format incredibly flexible. Almost any word could be turned into the beginning of a joke.

And once children understood the structure, they began inventing their own.

By the mid-1930s the trend had spread rapidly through American playgrounds and classrooms. What started as a simple novelty had suddenly become a nationwide joke craze.

Newspapers at the time began reporting on the trend with a mixture of amusement and irritation. Articles from 1936 describe children telling knock knock jokes so frequently that adults were beginning to complain. One syndicated humor column jokingly described Americans as being “under siege” from an endless stream of knock knock jokes delivered by enthusiastic children.

The fad grew so quickly that publishers began releasing joke books devoted entirely to the format. One of the earliest widely circulated titles was Knock Knock: Who’s There?, published in the mid-1930s. The book contained hundreds of variations of the same basic joke structure and sold extremely well.

Comedy writers noticed something interesting about the format. It allowed anyone to participate in humor without needing professional comedic skill. All you had to do was follow the structure and find a word that could turn into a pun.

In other words, it democratized comedy.

You did not need a stage, a microphone, or a script. You only needed someone willing to answer the question “Who’s there?”

The simplicity of the format also meant the jokes spread quickly through conversation. Long before the internet made jokes travel instantly, knock knock jokes moved from person to person at incredible speed.

By 1937, newspapers like The New York Times were reporting on the knock knock joke craze as a genuine cultural trend. Radio comedians occasionally referenced them. Teachers heard them constantly in classrooms. Parents heard them at dinner tables.

And like many fads, the enthusiasm eventually began to fade.

But something important had already happened.

The joke had entered childhood culture.

By the early 1940s the knock knock joke craze had largely run its course among adults. The novelty had worn off, comedians had moved on to other forms of humor, and newspapers stopped writing about the trend.

But the joke itself did not disappear.

Instead, it migrated almost entirely into the world of children.

Once a joke format becomes part of childhood culture, it gains a kind of longevity that most comedy never achieves. Children learn jokes from other children, and those jokes become part of playground folklore. As those children grow up, they often teach the same jokes to younger siblings or eventually to their own children.

In that way, the knock knock joke became something like a cultural hand-me-down.

Television helped reinforce that process. Beginning in the 1950s and continuing through later decades, knock knock jokes occasionally appeared in children’s programming and family entertainment. Writers understood that audiences already knew the rules of the joke, which meant the setup required almost no explanation.

A character could simply say “knock knock,” and viewers would instinctively understand what came next.

That shared understanding is part of what makes the format so resilient.

The joke has rules, and once people know the rules they can participate in the game.

For children especially, the appeal goes deeper than the punchline. Developmental psychologists have noted that young children often become fascinated with wordplay during early language development. Knock knock jokes rely heavily on puns and sounds that resemble other words, which helps children experiment with how language works.

In other words, the joke format doubles as a kind of linguistic puzzle.

For example:

Knock knock.
Who’s there?
Tank.
Tank who?
You’re welcome.

The humor depends on hearing “tank you” as “thank you.” Even when the joke itself is simple, the listener must mentally reinterpret the sounds to understand why it is funny.

That small moment of realization is satisfying, especially for children who are still discovering how flexible language can be.

By the 1970s and 1980s, knock knock jokes were firmly established as a staple of children’s humor. Joke books aimed at young readers frequently included entire sections devoted to them. School libraries stocked collections of puns and riddles built around the same structure.

For my childhood in the 80s, the most popular knock knock joke was this one.

Knock knock.

Who’s there?

Banana.

Banana who?

Knock knock.

Who’s there?

Banana.

Banana who?

Knock knock.

Who’s there?

Banana.

Banana who?

Knock knock.

Who’s there?

Orange.

Orange who?

Orange you glad I didn’t say banana?

Another popular one was one about an interrupting cow that’s appeared everywhere from the Simpsons to Modern Family.

The joke was co-opted for Fresh Prince of Bel Air where they took the same format as the interrupting cow and made it sensible for the time. It had to do with Amy Fisher and Joey Buttafuco.

Knock knock jokes were a format proved remarkably adaptable. New words could easily be turned into jokes, and children constantly invented new versions. Some became widely known while others existed only in small groups of friends.

Even as comedy evolved through stand-up specials, sitcoms, and eventually internet memes, the knock knock joke continued quietly passing from generation to generation.

And that might be the most fascinating part of its history.

Most comedy trends disappear quickly. Catchphrases fade. Viral jokes burn brightly and then vanish. But the knock knock joke has remained recognizable for nearly a century.

They’ve even been turned into anti-jokes like the one where you turn it around. “I know a knock knock joke. You start.”

“Knock knock”

“Who’s there?”

And then it’s awkward because they don’t know what to say.

The knock knock joke is short. It is interactive. It invites participation.

And it turns every listener into part of the performance.

So the next time someone begins a sentence with the words “knock knock,” they are not just telling a simple pun. They are continuing a tradition that surged across America in the 1930s, annoyed countless adults, delighted millions of children, and ultimately became one of the most durable joke formats ever created.

Which means that behind that tiny joke structure lies a surprisingly long cultural history.

And that history, strange as it may sound, is completely real.

Because the internet says it’s true.