Heat oven to 400°F.
Drizzle 2 tablespoons of the olive oil into 15x10-inch pan with sides.
Unroll dough. Cut each breadstick into 1/2-inch pieces. Place pieces in pan; drizzle evenly with remaining 1 tablespoon olive oil. Sprinkle evenly with dressing mix.
Bake 15 to 20 minutes, tossing croutons halfway through bake time, until golden brown on both sides.