Marinara and spaghetti sauce are both Italian tomato-based sauces but there are a few key differences between the two. Marinara sauce is typically made with tomatoes, garlic, onions, and herbs such as basil and oregano. It's generally thinner and smoother than spaghetti sauce and is often used as a base for other sauces, such as pizza sauce or pasta sauce. Spaghetti sauce usually contains more ingredients, such as meat, vegetables, and additional seasonings. It;s often used specifically as a sauce for spaghetti and other types of pasta dishes. Spaghetti sauce is also typically cooked for a longer period of time than marinara sauce in order to develop the flavors of the added ingredients.