Johnny Test season 2 has an official instrumental and a song called "Johnny Test Theme Song (HD)".

The first theme song was used in the Johnny Test cartoon.The first season's finale, Johnny and the Attack of the Monster Truck, was the only one in which it was used.

The words Johnny, followed by Test blink a few times as the theme song begins.The radioactivity sign is shown going down.Johnny drops from the top of the screen and lands atop the sign, and after it spins a few degrees, he flies to the lab, where he takes a radioactive chewing gum created by his sisters.As he eats it, he changes his name to Johnny X and wreaks havoc in the lab.Dukey is shown laughing as Johnny stops near him.

Dukey jumps on scoots and they leave the lab, going through the kitchen and upstairs to Johnny's room, where Hugh tries to make it shine.Johnny uses a surf board to surf on the junk when he opens the room.

The Extreme Teen Team, the Moonsies, Brain Freezer, Monkey Gil, and RoadBurn are shown in the scene.

There is a scene where Johnny is singing and morphing into different forms, such as Deep Sea Johnny, King of the Sea, Mega Muscle Johnny and Girl Johnny.The scene cuts back to the lab where Mary has her arms crossed as Susan pulls the lever down making the screen white and the Johnny Test logo appears.