Preheat your oven to 375°F (190°C).

Rinse the bell peppers, slice off the tops, and remove seeds.

In a large skillet over medium heat, add olive oil. Sauté chopped onion until translucent (about 5 minutes). Add minced garlic and cook for another minute.

Add ground turkey to the skillet; cook until browned. Stir in cooked rice, diced tomatoes, Italian seasoning, salt, and pepper.

Fill each pepper with the turkey mixture and place them upright in a baking dish.

Top with shredded mozzarella cheese. Cover with foil and bake for 30-35 minutes.

Let cool slightly before serving.