Before downloading, understand the components of your search:

The downloads you see online (often in or .zip formats) are typically fan-made "mods". These mods use the engine of an older PSP game—usually GTA: Liberty City Stories or GTA: Vice City Stories —and swap out textures, cars, and player skins to make it look like GTA V. The Reality of "GTA V PPSSPP" Files

If you're looking for alternative ways to play GTA V on Android, consider: