1. Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius). Spray two nine- by 13-inch (20- by 30-centimeter) baking pans with cooking spray.
2. Spread sweet potato slices in one pan and mushroom slices in the second.
3. Drizzle half of the olive oil, salt, and pepper over the sweet potatoes, and the other half over the mushrooms. Drizzle the teriyaki sauce over the mushrooms.
4. Toss the vegetables in each pan to coat. Bake for 20 minutes, turning vegetables over halfway through. Allow to cool.