It was challenging to show all four seasons within a 30-day filming schedule. Solutions included digitally darkening spring cherry blossoms to look like summer flowers and having crew members off camera throw falling silk leaves for autumn. There was a fluke snowstorm (unusual for March in Vancouver) and three different shots were coordinated that day before the snow could melt. Since fake snow can be expensive to put in a shot, this saved the film considerable money for the winter scenes.
Billie Joe Armstrong of Green Day enjoyed Bren's line "You didn't have to drive out to east Jesus nowhere" so much that on Green Day's album 21st Century Breakdown he wrote a song called "East Jesus Nowhere".
Jennifer Garner dropped her A-list salary to a percentage point agreement for Juno when it was expected to be a small, low-grossing indie film, but the decision paid off when Juno became a breakout smash at the box office - giving Garner her best payday yet.
The comic book "Most Fruitful Yuki" is a Japanese manga series. In 2001, it was published as a one-shot comic, but following its appearance in this movie, it has subsequently been translated into many languages (including English) and has gained a cult following.
The "pork swords" on the track team were achieved by hanging balls from the inside waist band of their shorts. Director Jason Reitman then asked the boys to kick up their knees as they ran so the balls would bounce.
The scene where Juno pulls the van over and cries on the side of the road was added after filming had already been completed and Ellen Page had gotten a hair cut. She is wearing a fake ponytail and her long bangs were trimmed into more of a face-frame cut that is visible in the shot.
Director Jason Reitman mentions on the DVD audio commentary that several objects in Bleeker's room, including a Hebrew alphabet poster on his door, a framed Bar Mitzvah certificate on his wall, and a dreidel on his shelf, are supposed to indicate that Bleeker is Jewish.
When searching for potential parents for her baby, Juno says she's looking for someone cool "like a graphic designer." In real life, both star Ellen Page's father and Diablo Cody's ex-husband are graphic designers.
Juno was the Roman Goddess of childbirth and marriage. The name "Juno" also has other meanings for Canadians (where Juno was filmed and a number of cast and crew - such as Ellen Page, Michael Cera and Jason Reitman - were born). "Juno" was the code name of the beach where Canadian troops landed on D-Day. Approximately 1000 Canadian soldiers were injured or killed on D-Day while capturing this beach. "Juno" is also the name of the annual Canadian music awards (similar to the U.S. Grammy awards).
Director Jason Reitman had intended to make the scene in which Juno loads up her tray in the school lunch line as tribute to a scene in Animal House (1978), which was produced by his father Ivan Reitman. But he decided against it because this would have changed the tone of the scene.
In an interview with The Guardian in May 2018, writer Diablo Cody said that the one thing she would have changed about the film is to make it clearer as to why Juno chooses not to have an abortion. She said "It was simply because she did not want to. It was not about any type of feeling that abortion was wrong - I'm pro choice." She also went on to say that the fact that some people have interpreted the movie as anti-choice is "upsetting."
Bren MacGuff, Juno's step-mom, has a nail parlor called "Bren's Ten." This is a reference to the Bren-Ten pistol, which was Don Johnson's sidearm of choice as Sonny Crockett in the '80s TV show "Miami Vice."
At one point, Juno questions the choice of her stepmother Bren (played by Allison Janney) to put her very young half-sister on ice skating lesson. Ten years later, Janney would win an Oscar for I, Tonya (2017), where she played Tonya Harding's abusive mother, who pushed her own daughter into becoming an ice skating champion from a very young age.