In February of 2007, Disney announced plans for a 2008 feature film sequel with a Halloween theme dubbed "Haunted High School Musical." In September of 2007, Disney said they had scrapped plans for the Halloween theme and instead will focus on the senior year of key characters at East High. According to Yahoo news, the original writer from the first two films, Peter Barsocchini, is writing the script. The original producers and director Kenny Ortega are also on board. Ortega confirmed this to Access Hollywood. Walt Disney Studios also released the following statement; "There is no contractual obligation for any of the cast members to return. That said, we are in active negotiations with all of the principle [sic] cast members and are feeling optimistic."
Zac Efron was quoted from People Magazine, saying: "I can tell you that if the script is good and if we all agree on a final script, then there's nothing that is going to hold us back from doing it. We have fun making these movies and that's very rare in this business."
Rumors persist of ongoing salary disputes between Disney and the lead performers, particularly Efron. According to Rachel Abramowitz, as reported online by the Chicago Tribune, "An eclectic cross-section of Hollywood insiders think Efron should get a cool $5 million for "High School Musical 3," the theatrical version of the franchise, which Disney is hoping to make prestrike -- i.e., in the next nine months, before a possible Writers Guild and Screen Actors Guild strike shuts down Hollywood." Efron declined to comment for the article, and "although contract negotiations still are ongoing, sources say Efron is being offered a salary closer to $3 million, not $5 million, for the follow-up, which focuses on senior year at East High.
Kenny Ortega, the director of HSM and HSM 2, has stated that Pre-production will most likely start in January 2008, and filming will begin in Spring 2008. He stated that the script has been submitted (before the Writers strike started) and that they are currently developing music. He added that filming will happen in Salt Lake City, Utah (as the first two films). He hinted that the plot will be something of the nature of the Wildcat's final year in High School and stated "it looks like we've rounded up the cast.