Whether or not a grill pan needs oil depends on the food you're cooking and your personal preference. While some foods, like fatty meats, may release enough natural fats to prevent sticking, others may benefit from a light coating of oil on the pan's surface. Using oil can help prevent sticking and promote even cooking, especially for lean meats and vegetables. However, it's essential to use oil sparingly to avoid excessive smoke and maintain the integrity of the grill pan's non-stick coating.