Yes, a Bully Dog GT Tuner can be used on multiple vehicles. However, you will need to purchase a new tune file for each vehicle. The GT Tuner comes with one pre-loaded tune file, but additional files can be purchased from Bully Dog. Once you have the appropriate tune file loaded onto your GT Tuner, simply plug it into the OBD-II port of your desired vehicle and follow the prompts on the device to complete the tuning process.