Preheat your grill to medium-high heat.
In a large bowl, toss the halved Brussels sprouts with olive oil, garlic powder, salt, and pepper until well coated.
Place the Brussels sprouts on the grill, cut side down, and grill for about 5-7 minutes until they are nicely charred.
Flip the sprouts and grill for an additional 5 minutes until they are tender.
In a small saucepan, combine balsamic vinegar and honey (if using) over medium heat. Simmer for 3-5 minutes until slightly thickened.
Remove the Brussels sprouts from the grill and drizzle with the balsamic glaze before serving.