Mexican street food, called antojitos (literally "little cravings"), is prepared by street vendors and at small traditional markets in Mexico. Street foods include tacos, tamales, gorditas, quesadillas, empalmes, tostadas, chalupa, elote, tlayudas, cemita, pambazo, empanada, nachos, chilaquiles, fajitas, tortas, even hamburgers and hot dogs, as well as fresh fruits, vegetables, beverages and soups such as menudo, pozole and pancita. Most are available in the morning and the evening, as mid-afternoon is the time for the main formal meal of the day. Mexico has one of the most extensive street food cultures in Latin America, and Forbes named Mexico City as one of the foremost cities in the world in which to eat on the street.

In Mexican Spanish, the fast foods prepared on the streets and in market stalls are called antojitos (literally "little cravings") because they are typically foods not eaten at a formal meal, especially not the main meal of the day, la comida, which is served in the mid-afternoon. However, there are exceptions. Street foods are easiest to find in the early morning and then the evening and late into the night. They are harder to find, outside Mexico City, in the mid-afternoon. The majority of the food is corn-based. It is also found at street markets called "mercado sobre ruedas" and tianguis. Other areas in Mexico City noted for their street food are San Pedro de los Pinos market, Mercado San Juan Arcos de Belen, Calle López in the historic center and the Mercado de Antojitos ("street food market") in Coyoacán.

In Latin America, Mexico has one of the most extensive street food cultures, with about 43% of the population believing that it is not harmful and about 58% eating on the street at least once a week. Mexican food was named by UNESCO as an intangible cultural heritage of mankind, and Forbes named Mexico City one of the top ten cities for street food in the world. Street and market food has had a significant impact on haute cuisine in Mexico, with upscale restaurants serving many of the same foods as in the streets, sometimes modified and sometimes not. It has influenced the United States, where Houston chef Hugo Ortega and Chicago chef Rick Bayless both published books dedicated to Mexico's street food. Chefs come to Mexico to investigate the local cuisines as Mexican food in general becomes more appreciated. This includes street foods. In the United States, Mexican-style street food can be found in small counter-service restaurants and the variety being demanded goes beyond Tex-Mex into the regional foods of Mexico. With more than 100 years of Mexican-style street food history, Los Angeles is known for its street food lunch trucks, serving tacos, tortas, quesadillas and more. Tacos can follow the traditional recipes of Mexico or be more creative. The University of California, Los Angeles held a conference on Mexican street food, where it was distinguished from typical fast food by cultural considerations.

The taco is a folded tortilla with some kind of filling. Mexican street taco fillings vary from one region to another. Most tacos are made with corn tortillas, except in the very north of the country where wheat flour tortillas dominate. The tortillas used in Mexican tacos are soft, although the entire taco can be fried, which is called "dorado" (lit. golden). The taco has its origins in the pre-Hispanic period, when other foods were eaten with tortillas, and used as a scoop. The modern taco developed in Mexico's rural areas when wives would bring their husbands' meals to the fields wrapped in tortillas. Tacos arrived in the city when stands began to sell foods known to the many rural people who migrated to them in the 20th century. This is especially true for Mexico City, which offers taco specialties from just about every region of the country. The taco bridges social and economic barriers in that everyone in the country eats it, leading it to be called "the most democratic of Mexican foods."

The fillings for tacos vary widely and most taco vendors have a specialty, the most known are al pastor and bistec. There are also tacos for more adventurous people that are filled with beef eyes, brains, or tongue. Taco vendors are usually distinguished from other street food vendors by having a large block of wood called a tronco, on which meat and other fillings are minced with a cleaver. Garnishes vary but usually include chopped onion, cilantro, various salsas, grilled green onions, and lime wedges. Many taco varieties are generally available only in the morning or afternoon. Tacos most often found in the morning hours include tacos de canasta and those with barbacoa or cabeza de res (lit. beef head). Tacos de canasta (basket tacos) are the only kind that are not prepared on the spot. They are tortillas with fillings such as potatoes, chorizo sausage, pork rind, beans and picadillo (a spiced ground meat), then steamed and wrapped to keep warm and carried in a basket. Barbacoa is pit-roasted meat. It is most commonly found in the center of the country, where the preferred meat is mutton. In the north of the country, there is a version made with beef. Cabeza de res are made from meat and other parts of a steer, most commonly found in Sonora, the Bajío region and Mexico City. Vendors of these kinds of tacos usually sell out and close by midday.

During the afternoon, outside of Mexico City, tacos are generally not available until later in the day. In the late afternoon until well into the night (especially on weekends) other taco stalls open with a different selection. These are principally grilled, fried, or steamed meat. One famous night taco in the Mexico City area is tacos al pastor (shepherd-style tacos). They are an adaptation of Middle Eastern spit-cooked meat, introduced by Lebanese immigrants. However, the meat is pork and the seasoning is a mild chili pepper, onions and pineapple. Other taco varieties include tacos de guisado, or tacos de cazuela, which are filled with meat or vegetables in a sauce.

Fritangas are tacos with fried meat such as sausage. Carnitas is pork cooked in lard flavored with orange rind. It was originally a specialty of Michoacán and Jalisco, but now can be found in most of the center of the country and in other parts of the country as well. The best-known grilled taco is carne asada (grilled meat) which originated in Sonora. It is beef grilled over charcoal, originally mesquite. These are served with grilled green onions and, depending on the region, served with flour or corn tortillas. Fish tacos are a speciality of Baja California and the Pacific coast. They have also become very popular in parts of the United States. Codzitos are small tacos popular in the Yucatán Peninsula, which are fastened with toothpicks and then fried. Flautas, also called taquitos or tacos dorados, are similar to tacos in that they are filled, but they are then rolled and fried. They are served topped with cream, salsa, and vegetables such as lettuce, tomatoes and onions.

Tamales feature a filling and are wrapped in corn-based masa dough and steamed in corn husks. Tamales come in sweet and savory versions, some spicy and some bland. Versions with pork or chicken with a salsa or mole sauce are the most popular, along with a version called "rajas" that are filled with strips of poblano chili pepper and cheese. It is one of the safer street foods for novices to try as it is cooked and kept in a steam vat while being sold. Corundas are a variety of tamale in Michoacán in a triangle shape wrapped in corn stalk leaves. They can be eaten alone, with salsa or as an accompaniment to a meal. The Chiapas version of the tamale has a distinct flavor, often containing ingredients such as pibil, mole sauce, carrot, corn grains, egg, raisins, almonds (known locally as nacatamales, a regional version of Nicaraguan well-known version), a version with the regional herb chipilín with chicken or queso blanco and versions wrapped in banana leaves. They are often sold by vendors on specially made tricycles for street vendors. Uchepos are tamales made with fresh corn, generally made in Michoacán in July and August.