Banh mi is a Vietnamese sandwich which is famous for being extremely hearty and relatively inexpensive. In its native Vietnam, banh mi is a common offering at many restaurants and street stalls, and in regions of the world with a large Vietnamese community, the sandwich is also extremely common. In both cases, there are a number of configurations to choose from, with ingredients which range from shredded barbecued pork to tofu, and seasoning which can be mild to intensely spicy.

The development of the banh mi did not begin until the French colonized Vietnam, introducing people to the baguette, a type of long, thin, crusty French bread. The French colonists developed a sort of salad sandwich, taking advantage of locally available Vietnamese ingredients like fresh greens, pickled vegetables, and spicy chiles, and the early form of banh mi was born. While the French have left Vietnam, the taste for banh mi has stayed on.

This sandwich is analogous to the submarine sandwich in the United States, which is also known as a hoagie, po' boy, hero, grinder, wedge, or Italian, among many other alternate names. However, banh mi has a few distinctive traits which set it aside from this well known American sandwich. The first is the inclusion of classically Asian ingredients like daikon radish, coriander, pickled carrots, sriracha chili sauce, tofu, and spring onions. The second is the seasoning used on the meats, when meat is included; the meat typically has a distinctively Vietnamese feel.

Pork, beef, and chicken are all used in banh mi, sometimes even together. The sandwich can also include ingredients like eggs for a breakfast sandwich, and ingredients like seitan, tempeh, and textured vegetable protein are not unknown in vegetarian versions. In all cases, banh mi typically has a healthy balance of fresh greens and vegetables blended with meats.

Some people call the banh mi a sort of kitchen sink sandwich, meaning that cooks throw in whatever they have lying around the house. Whether banh mi is assembled from leftovers or from ingredients which are specifically purposed, it tends to be very filling, with the ingredients typically attempting to explode from the baguette. Most people are accustomed to very inexpensive banh mi, making it a popular street food and quick meal.