Petrucci has two groups of primary influences, “…the Steve’s and the Al’s”. The Steve’s are Steve Morse, Steve Howe, Steve Vai, and Stevie Ray Vaughan. The Al’s are Alex Lifeson, Al Di Meola, and Allan Holdsworth.
Some of his early influences include Steve Morse, Al DiMeola, Steve Howe, Allan Holdsworth, Stevie Ray Vaughan, Randy Rhoads, Joe Satriani, Steve Vai, Alex Lifeson, Yngwie Malmsteen, Rush, Yes, Iron Maiden, The Dregs and Metallica.
In Ultimate Classic Rock, JP said:
It started with liking classic rock. Where I lived, on Long Island, you had the radio stations that always played Led Zeppelin and Pink Floyd, Black Sabbath and AC/DC and all that. I grew up on all that stuff. I got turned onto bands — you know, the first time I heard Rush, the first time I heard Yes. Then, my mind started to want to connect and reach out to some other things. Then, Iron Maiden came along, and Metallica, and all this other stuff.
When asked which guitarist stands the most out:
For me it was Steve Morse,” Petrucci explained. “It was funny. I started playing guitar and getting into [Led] Zeppelin, Rush, ACDC, Sabbath and stuff like that, and one of my friend’s friends was like ‘Dude you got to check this out,’ and it was the [Dixie] Dregs.
When asked about more modern progressive metal acts:
I think that without naming a specific band, there is a whole wave of younger bands that are in the prog vein. There is Periphery, Between the Buried and Me, Animals As Leaders — bands like that are doing stuff where you hear it and you are like, ‘Wow, that’s amazing! That was intense!’