The main difference between a grill pan and a griddle lies in their surfaces and cooking methods. A grill pan typically has raised ridges or grooves that mimic the grilling marks you'd get from an outdoor grill. It's ideal for cooking meats, vegetables, and seafood, allowing excess fat to drip away and creating those desirable grill marks. On the other hand, a griddle features a flat, smooth surface, perfect for cooking pancakes, eggs, bacon, and other breakfast foods. While both are used for stovetop cooking, the choice between a grill pan and a griddle depends on the type of food you want to cook and the cooking method you prefer.