Preheat the oven to 400F. Lightly grease a large baking sheet with olive oil or cooking spray.
Add the butternut squash, Brussels sprouts, and beets to the baking sheet, making separate rows of each. Drizzle the veggies with olive oil and season with salt, pepper, and garlic powder. Toss the veggies to combine, keeping them in separate rows (if you combine all of them the beets will change the color of the other veggies).
Bake for 35-40 minutes until the veggies are golden brown and tender.