The premiere pulled in 1.2 million individuals with an 8.4% audience share across multichannel homes. Over its two-hour slot its audience peaked at 1.3 million.
An average of 750,000 kids - an audience share of 38.4% - tuned in for the premiere, giving the channel the biggest audience among kids on Friday, beating EastEnders and Coronation Street.
High School Musical 2 pushed Disney Channel UK's audience day share to 19.8%, its best ever among kids across multichannel homes.
Disney Channel UK managing director Rob Gilby said: "Kids around the world are as enthusiastic as ever for High School Musical and these UK viewing figures for the sequel show there is continued appreciation for the music, the characters and the stories kids find relevant to their lives."
The channel's four showings for the movie saw a collective 1.74 million viewers tuning in, with overnight figures reporting that 1 million were kids aged 4-15.
In the US, the movie was watched by 17.2 million when it premiered last month.