Preheat the oven to 400 degrees F (200 degrees C).
Spread sweet potato slices evenly on 2 cookie sheets. Coat evenly with cooking spray; sprinkle 1/2 of the garlic-pepper seasoning on top.
Bake in the preheated oven for 15 minutes. Flip, spray on the second side, and sprinkle remaining seasoning on top. Continue baking until tender, about 15 minutes more.
