Preheat the air fryer to 400°F (200°C).
In a medium bowl, toss the frozen Brussels sprouts with olive oil, salt, pepper, and garlic powder until evenly coated.
Place the seasoned sprouts in the air fryer basket in a single layer to ensure proper airflow.
Cook for 10 minutes at 400°F (200°C).
Remove the basket and shake well to redistribute the sprouts for even browning.
Continue cooking for 5 to 7 minutes or until the outer leaves are charred and the centers are tender.
Transfer to a serving dish and serve immediately while hot.