In a large skillet, heat olive oil over medium heat. Add the Italian sausage and cook until browned, about 5-7 minutes.

Remove the sausage from the skillet and set aside. In the same skillet, add sliced bell peppers, onion, and garlic. Sauté until the vegetables are tender, about 5-7 minutes.

Return the sausage to the skillet with the vegetables. Add Italian seasoning, salt, and pepper. Stir to combine and cook for an additional 10 minutes, allowing the flavors to meld.

Serve hot, either on its own or in a sub roll for a sandwich.