The movie was filmed at East High School in Salt Lake City, Utah. Students still use Sharpay's pink locker.

Ashley Tisdale originally auditioned for the role of Gabriella Montez, but director Kenny Ortega thought she would do better in the role of Sharpay Evans.

The cell phone ring that gives the class detention has the tune of the song "Start of Something New."

Zac Efron and Vanessa Hudgens were dating both on and off the screen.

Zac Efron's singing voice was that of Drew Seeley, who tested for the role of Troy. Seeley sang the entirety of "Get'cha Head in the Game" and the reprise of "What I've Been Looking For." Efron only sings the first four lines of "Start of Something New," the first sentence of "Breaking Free," and during the scene on the balcony. The reason for this is because Efron's natural voice was too low for that of a tenor and the producers wanted a tenor to match the role. Efron did, however, do all of his own singing in the sequels, as all the music in those films had been tailored specifically for his voice.

It took 24 days to film this movie.

Matthew Underwood from Zoey 101 (2005) was offered the role of Troy Bolton, but because of his contract with Nickelodeon, he was forced to decline the role.

The falling snow in the New Year's scenes was potato flakes.

Corbin Bleu came up with the slogans that appear on the shirts that he wears in the movie.

According to Corbin Bleu, whenever the principal cast members get together, they always discuss doing a High School Musical reunion. Bleu has said, "the question isn't if we're going to do one, the question is when we're going to do one."

On January 20, 2016, the original cast came together to celebrate the 10th anniversary of the release of the movie. However, Zac Efron was busy promoting his film Dirty Grandpa (2016) and was unable to attend. His only appearance was a prerecorded message in which he stated which scene from the franchise was his favorite (the scene was "We're All In This Together").

A duet between Coach Bolton and Ms. Darbus was planned but never filmed.

Zac Efron had to undergo three hours of basketball practice every day because his character was the captain of the basketball team.

In Corbin Bleu's first appearance at the school, he was wearing three different watches. He was given a choice of which one he wanted to wear, so he chose all three of them. Each was set to different time zones.

Over 600 teen actors auditioned for this movie.

Corbin Bleu originally intended to audition for Ryan Evans, but when he saw Lucas Grabeel dancing at the audition, Corbin said that he couldn't shake like Lucas, and Ryan had to shake when dancing. Instead, he auditioned for Chad and won the role.

"High School Musical" was the working title for the film while producers brainstormed a better name. However, by the time of post-production, there were no better options, and so the producers unwillingly settled for "High School Musical."

The school's mascot was going to be a leopard, but it was changed to a wildcat.

The soundtrack was recorded in five days.

One of the first films to be offered for sale at the iTunes Store.

One of the players playing for the Wildcats in the championship game wore a jersey with the word "extra" on the back.

The rooftop scene had to be cut short since a real thunderstorm was headed toward the school.

In the beginning scene, the room where Troy and his dad played basketball was actually a room in the school where they shot most of the movie. It was actually a dance studio, but they covered the mirrors. You can see ballet barres in the back.

The film has its origins in a 1999 script entitled "Grease 3." Britney Spears and Justin Timberlake were to star as the children of Danny Zuko and Sandy Olsson from the 1978 film. The plot was virtually the same as that High School Musical, but with more similarities to Grease (1978). The character who would become Sharpay was to be the daughter of Betty Rizzo (producers tried to get Christina Aguilera for the part, but she declined). Timberlake's bandmates from *NSYNC were to have supporting roles, with John Travolta and Olivia Newton-John allegedly approached for cameo roles. Before the script went through a second rewrite, the project was shelved until 2004. Producers would have needed permission from those who owned the rights to Grease (1978), and so the idea evolved into High School Musical.

Many of the items in the rooftop garden scene were placed there by a crane. After filming was completed, some of the teachers wanted the garden to remain on the rooftop.

Ashley Tisdale (Sharpay Evans), was also working on the second season of The Suite Life of Zack & Cody (2005) while filming this movie.

There are several noticeable attempts to set Troy and Gabriella apart from the people around them by placing them both in blue outfits. One strong example is the shot of Troy, the Wildcats, and the cheering fans seen out the window immediately before Gabriella sings "When There Was Me and You." At this point, Troy essentially looks like a blue spot in a sea of red.

Ashley Tisdale came up with the idea for her scene kicking the bathroom doors.

Lucas Grabeel wore nine different hats during the movie.

This was the Disney Channel's most successful movie at its time with 7.7 million viewers in the premiere broadcast. The Cheetah Girls 2 (2006) broke this record with 8.3 million viewers on its premiere night. High School Musical 2 now stands as the highest rated Disney Channel original movie premiere with more than 17.2 million viewers.

Lucas Grabeel and Olesya Rulin had previously worked together on Halloweentown High (2004).

Some of the items on Gabriella's tray were glued to the tray.

The championship trophy held by Troy at the end was made in 1936.

Gabriella sings the only solo in this movie.

Grabeel had knee problems while filming High School Musical and was wearing a knee brace in "Bop to the Top."

Disney Channel executives and producers originally wanted Cassie Steele to play Gabriella after seeing her in another Disney Channel original movie, Full-Court Miracle (2003). She auditioned several times and had a screen test, and was cast as Gabriella. However, the fifth season of her television show, Degrassi: The Next Generation (2001), seriously conflicted with the filming of this movie, causing Steele to drop out.

The cast had to undergo two weeks of intense dance rehearsals before filming began on the movie.

Of the six main cast members, Corbin Bleu was the youngest (17 at the time of the film's release) and Monique Coleman was the oldest (25 at the film's release).

The moon that was seen on stage while Troy and Gabriella are singing "Breaking Free" was left behind on stage after the film was completed.

At the time Coleman was called back to play Taylor McKessie, she had nearly quit acting. Even after being offered the part, she reluctantly accepted.

Vanessa Hudgens had to compete with 12 other girls for the role of Gabriella Montez during the callbacks for this movie. She and the other girls danced and sang all day to determine who would play Gabriella Montez.

The final callback for Taylor came down to Coleman and two Asian-American actresses. She feared she wouldn't get the role because of her hair. Coleman claimed it resembled Corbin Bleu's hair; she thought they looked too much like siblings.

Kelsi's fall had to be shot many times because the paper would either stick together or fly off stage.

The milk cartons seen in the movie did not contain milk. They contained lemon-lime juice because milk spoils if it is not refrigerated.

At the second callback, Grabeel and Tisdale auditioned together and their Sharpay-Ryan dynamic was quickly established. Grabeel claimed that Tisdale, in a Sharpay-like manner, gave him unsolicited direction in the audition. It was rumored that the two actors did not get along in the first film. The audition experience may have been the cause.

During one of the lunchroom scenes, a large spotlight was accidentally dropped off an upper two story balcony, almost hitting some of the film crew below.

In its first week of release, the soundtrack to High School Musical debuted at #143 on the Billboard Top 200 and sold 6,500 copies. It went on to sell 4.1 million copies, making it the best-selling album in America in 2006.

Filming in a real high school, East High in Salt Lake City, created some challenges and they were only able to use certain parts of the school at certain times because class was in session.

Vanessa Hudgens said that her favorite scene in the movie was the final scene where the entire cast sang and danced to "We're All in this Together".

Naya Rivera from Glee auditioned for Gabriela in High School Musical but didn't get the part.

In the championship game if you look at the scoreboard at the end of the game, you can see that Troy was the last person to foul and had received 3 fouls in the game.

Sharpay Evans is left handed.

Lucas Grabeel originally auditioned to play Troy Bolton.

Ashley Tisdale dyed her hair and became a blonde for the part of Sharpay Evans in HSM1-3 as well in a spin-off Sharpay's Fabulous Adventures. She has since switched back to natural brunnette leaving the Sharpay image behind her for good. She is still a brunette.

Hunter Parrish auditioned for the role of Troy Bolton. He and Zac Efron went on to work together in 17 Again (2009).

Casey Bartholomew, a popular radio talk show host from KFI in Los Angeles, WDBO in Orlando, and New Jersey 101.5 in New Jersey, is in the crowd of the championship basketball game.

In the "We're all in this together scene" some of the cheerleaders can be seen doing a dance that contains a dab.

Julian Nott had hoped to write the music for the film, but he was replaced before he had begun the scoring process. Some promotional posters still say "Music by Julian Nott."

In the two weeks following the first presentation of this movie on the Disney Channel, at least 8 tracks from the movie appeared on the Billboard Hot 100, the most simultaneous songs ever from one album at that point in time. In addition, many other Hot 100 chart records were set or broken. These include: First debut artist to have 2 Hot 100 singles in the same week: Zac Efron. (Tied the next week by both Lucas Gabreel & Ashley Tisdale.) First artist to debut with 4 Hot 100 singles in two weeks: Zac Efron. (The Beatles first three chart records were over a four week span.) First duo to have 3 Hot 100 debut singles appear in 2 weeks on the Hot 100: Zac Efron and Vanessa Anne Hudgens. First duo to have 2 Hot 100 debut singles in the same week: Lucas Gabreel & Ashley Tisdale. First female to have 3 debut chart credits in 2 weeks: Vanessa Anne Hudgens. First female to have 2 debut chart credits in 1 week: Ashley Tisdale Biggest jump in Hot 100 history: (86-4) 82 points, "Breaking Free" by Zac & Vanessa. (Trouncing the old record of 74-point leaps shared by Montell Jordan's "I Can Do That" and Jeannie C Riley's "Harper Valley PTA".) First time an artist has appeared on 5 concurrent Hot 100 singles within one week of his debut: Zac Efron. (Zac's 5 concurrent songs in the Hot 100 were the most by any artist since the Beatles held 14 positions in 1964.)

Ashley Tisdale, Vanessa Hudgens, and Monique Coleman also worked together on The Suite Life of Zack and Cody. Ashley played a main role throughout the entire series, while Vanessa and Monique guest starred in various episodes during season 2. Zac Efron also guest starred in one episode in season 1.

The actor who plays the principal for East High also played the Palos Verdes girl's basketball coach in another D-Com, "Double Teamed" (2002).

Jason's surname is Cross.

The auditorium was located at another school because the one at the school where they did the majority of filming was being renovated.

In 2010, the comedy company RiffTrax released a humorous commentary for "High School Musical," riffed by MST3K alumni Mike Nelson, Bill Corbett and Kevin Murphy.

Grabeel asked Ortega about Ryan's sexuality very early on. There was never confirmation either way; although, Ryan appears to show interest in Kelsi in the third film. However, that being said, both Grabeel and Ortega said that they believed Ryan should be gay, but Disney wouldn't allow them to use that in a family film.