Is There a Guitar Hero Game on PSP? No — But Rock Band Unplugged Is the Alternative
No mainline Guitar Hero game was released on PSP.
What *Was* on PSP (Rhythm Games)
Guitar Hero: On Tour (2008) — Nintendo DS ONLY (Guitar Grip accessory).
Rock Band Unplugged (2009) — PSP Exclusive. Developed by Backbone. Touchscreen/buttons for lanes. No peripheral. Excellent setlist (Master Tracks). This is the closest equivalent.
DJ Max Portable / Clazziquai / Black Square / Technika Tune: Korean arcade-style rhythm. Button-heavy. High difficulty.
Guitar Rock Tour (Gameloft, 2008): Mobile port (iOS/DS/Feature phones). Not on PSP officially.
Why No GH on PSP?
UMD load times killed rhythm precision.
No viable peripheral (DS had Grip; PSP had no port for one).
Activision prioritized DS (higher install base) and home consoles.
Recommendation: Play Rock Band Unplugged on PSP (PPSSPP emulator upscales beautifully). Or Clone Hero (PC, free, custom songs, supports any controller).