The movie released Aug 29, 2008.
Its writer-director Abhishek Kapoor tweeted Friday: "HBD #rockon!! 6 yrs ago, u made a diff and changed lives.. @rampalarjun @FarOutAkhtar @Purab_Kohli and a shout out 2 all who made it happen."
The film, a rock musical, launched the acting careers of Prachi Desai and Farhan Akhtar. Farhan even produced the film, which also stars Arjun Rampal, Luke Kenny and Purab Kohli.
Farhan tweeted: "Happy 6th Movieversary to the entire team of Rock On!! ... Shine On beautiful people", while Arjun posted: "Happy Anniversary Rock On!!!"
The film, which had blockbuster music by Shankar-Ehsaan-Loy, is about the fate of a Mumbai-based rock band Magik, members of which reunite after a decade-long split.