Preheat oven to 375 degrees F (190 degrees C). Cut the tops off the bell peppers and remove seeds. Place peppers in a baking dish.
In a large skillet over medium heat, heat olive oil. Add onion and garlic; cook until softened, about 5 minutes. Stir in rice, tomatoes, oregano, basil, salt and pepper.
Fill each pepper with the rice mixture. Replace tops of peppers.
Bake in preheated oven for 40 minutes or until peppers are tender.