Preheat oven to 425°.
Combine potatoes and olive oil in a large bowl; toss well to coat. Arrange potatoes in a single layer on a baking sheet coated with cooking spray. Bake at 425° for 35 minutes or until golden brown, turning 2 times.
Combine thyme, salt, and pepper in a small bowl. Sprinkle potatoes evenly with thyme mixture; toss to coat.