Preheat your oven to 375°F (190°C).
Cut the tops off the bell peppers and remove the seeds.
In a skillet, sauté onion and garlic until translucent.
Add ground beef and cook until browned.
Stir in diced tomatoes, cooked rice, and Italian seasoning.
Season the mixture with salt and pepper to taste.
Fill each bell pepper with the meat and rice mixture.
Top each pepper with shredded cheese.
Place stuffed peppers in a baking dish and cover with foil.
Bake for 25 minutes, then remove foil and bake for an additional 5 minutes.