Place the butternut squash, carrots, sweet potato, rutabaga, parsnips, and turnips into a large mixing bowl. Drizzle with olive oil, and toss to coat. Season to taste with kosher salt and pepper, and place the vegetables into a deep roasting pan.
Roast in the preheated oven until the vegetables have lightly browned around the edges and are tender, about 45 minutes. Stir once as the vegetables roast to ensure even cooking.