Wash the bell peppers, cut the tops off, and remove seeds and membranes. Brush with olive oil and place in a baking dish.
In a skillet, heat olive oil, sauté onion and garlic for 3-4 minutes. Add ground turkey, cook until browned (5-7 minutes).
Cook rice according to package instructions if not already prepared.
Mix cooked rice, diced tomatoes, Italian seasoning, salt, and black pepper into the turkey mixture. Simmer for 5 minutes.
Stir in half of the shredded cheese into the filling. Stuff the peppers with the mixture.
Top each pepper with remaining cheese. Cover with foil and bake for 25 minutes, then uncover and bake for an additional 10-15 minutes until cheese is bubbly.
Let the peppers cool for a few minutes before serving.