Preheat oven to 450°F.
Combine green beans, garlic, oil, salt, and pepper in a large bowl, tossing to coat.
Spread in a single layer on a rimmed baking sheet.
Bake in preheated oven until green beans are tender, 15 to 20 minutes, stirring halfway through.
Sprinkle green beans with Parmesan, and continue to bake until Parmesan has melted, about 1 minute.
Remove from oven, and sprinkle with bacon. Serve immediately.
