Neapolitan pizza (pizza napoletana): Authentic Neapolitan pizzas are made with local ingredients like San Marzano tomatoes, which grow on the volcanic plains to the south of Mount Vesuvius, and Mozzarella di Bufala Campana, made with the milk from water buffalo raised in the marshlands of Campania and Lazio in a semi-wild state (this mozzarella is protected with its own European protected designation of origin).[1] According to the rules proposed by the Associazione Verace Pizza Napoletana, the genuine Neapolitan pizza dough consists of Italian wheat flour (type 0 or 00, or a mixture of both), natural Neapolitan yeast or brewer's yeast, salt and water. For proper results, strong flour with high protein content (as used for bread-making rather than cakes) must be used. The dough must be kneaded by hand or with a low-speed mixer. After the rising process, the dough must be formed by hand without the help of a rolling pin or other mechanical device, and may be no more than 3 mm (¹⁄₈ in) thick. The pizza must be baked for 60–90 seconds in a 485 °C (905 °F) stone oven with an oak-wood fire.[2] When cooked, it should be crispy, tender and fragrant. Neapolitan pizza has been given the status of a "guaranteed traditional specialty" in Italy. This allows only three official variants: pizza marinara, which is made with tomato, garlic, oregano and extra virgin olive oil (although most Neapolitan pizzerias also add basil to the marinara), pizza Margherita, made with tomato, sliced mozzarella, basil and extra-virgin olive oil, and pizza Margherita extra made with tomato, buffalo mozzarella from Campania in fillets, basil and extra virgin olive oil.

Pizza al taglio in RomeLazio style: Pizza in Lazio (Rome), as well as in many other parts of Italy is available in two different styles: (1) Take-away shops sell pizza rustica or pizza al taglio. This pizza is cooked in long, rectangular baking pans and relatively thick (1–2 cm). The crust is similar to that of an English muffin, and the pizza is often cooked in an electric oven. It is usually cut with scissors or a knife and sold by weight. (2) In pizza restaurants (pizzerias), pizza is served in a dish in its traditional round shape. It has a thin, crisp base quite different to the thicker and softer Neapolitan style base. It is usually cooked in a wood-fired oven, giving the pizza its unique flavor and texture. In Rome, a pizza napoletana is topped with tomato, mozzarella, anchovies and oil (thus, what in Naples is called pizza romana, in Rome is called pizza napoletana).

Other types of Lazio-style pizza include:

Pizza romana (in Naples): tomato, mozzarella, anchovies, oregano, oil;
Pizza viennese: tomato, mozzarella, German sausage, oregano, oil;
Pizza capricciosa ("capricious pizza"): mozzarella, tomato, mushrooms, artichokes, cooked ham, olives, oil (in Rome, prosciutto raw ham is used and half a hard-boiled egg is added);
Pizza quattro stagioni ("four seasons pizza"): same ingredients for the capricciosa, but ingredients not mixed;
Pizza quattro formaggi ("four cheese pizza"): tomatoes, mozzarella, stracchino, fontina, gorgonzola (sometimes ricotta can be swapped for one of the last three);
Sicilian-style pizza has its toppings baked directly into the crust. An authentic recipe uses neither cheese nor anchovies. "Sicilian" pizza in the United States is typically a different variety of product made with a thick crust characterized by a rectangular shape and topped with tomato sauce and cheese (and optional toppings). Pizza Hut's "Sicilian Pizza", introduced in 1994, is not an authentic example of the style as only garlic, basil, and oregano are mixed into the crust;
White pizza (pizza bianca) uses tomato sauce, often substituting pesto or dairy products such as sour cream. Most commonly, especially on the east coast of the United States, the toppings consist only of mozzarella and ricotta cheese drizzled with olive oil and spices like fresh basil and garlic. In Rome, the term pizza bianca refers to a type of bread topped with olive oil, salt and, occasionally, rosemary leaves. It’s also a Roman style to bottom the white pizza with figs, the result called pizza e fichi (pizza with figs);
Ripieno or calzone is a pizza in the form of a half moon, sometimes filled with ricotta, salami and mozzarella; it can be either fried or oven baked.

Non-Italian types of pizza
In the 20th century and onward, pizza has become an international food and the toppings may vary considerably in accordance with local tastes. These pizzas consist of the same basic design but include an exceptionally diverse choice of ingredients.

United States styles and specialties
 
Home-made pepperoni pizzaDue to the wide influence of Italian and Greek immigrants in American culture, the United States has developed quite a large number of regional forms of pizza, many bearing only a casual resemblance to the Italian original. During the latter half of the 20th century, pizza in the United States became an iconic dish of considerable popularity. The thickness of the crust depends on what the consumer prefers; both thick and thin crust are popular. Often, "Americanized" foods such as barbecued chicken and bacon cheeseburgers are used to create new types of pizza. Mexican pizza, or taco pizza, is also popular in the U.S., popularized by the Taco Bell chain.

Ingredients
 
A home-made pizza exhibiting a plethora of toppings common to American pizzasAmerican pizza often has vegetable oil or shortening (often, but not always, olive oil) mixed into the dough; this is not as common in Italian recipes (for example, the pizza dough recipe in the influential Italian cookbook Il cucchiaio d'argento does not use oil). This can range from a small amount in relatively lean doughs, such as New York style, to a very large amount in some recipes for Chicago-style deep-dish dough. In addition, American pizza (at least thin-crust) is often made with a very high-gluten flour (often 13–14% protein content) of the type also used to make bagels; this type of flour allows the dough to be stretched rather thinly without tearing, similar to strudel or phyllo dough.

Various toppings may be added, most typically:

Tomato sauce usually replaces the tomato Irsyad used on Italian-style pizzas, and is usually a fairly heavily seasoned, smooth sauce with a low water content. On some variants without tomatoes, pesto, alfredo and barbecue sauce are also used.
Cheese, usually mozzarella but also provolone, cheddar, parmesan, feta, or a blend of other cheeses.
Fruits and vegetables such as garlic, artichoke hearts, eggplant, olives, capers, onions, spinach, tomatoes, crushed red pepper, bell peppers, green chili peppers, jalapeños, banana peppers and pineapple.
Fungi, usually Mushrooms and rarely truffles.
Meat, such as sausage (pepperoni, salami or Italian sausage), ham, bacon, ground beef, and chicken.
Seafood such as anchovies, tuna, salmon and shrimp.
Herbs and spices such as basil, oregano, black pepper and chili pepper.
Nuts such as cashews, pistachios and pine nuts.
Oils such as olive oil, walnut oil and truffle oil.
In some pizza recipes the tomato sauce is omitted (termed "white pizza"), or replaced with another sauce (usually garlic butter, but sauces can also be made with spinach or onions). In the Philadelphia area there are also tomato pies—sauce only, or sauce with ripe Roma tomatoes and spices but no cheese—and upside-down pizzas, i.e., the cheese on the bottom and topped with sauce. Pizza is normally eaten hot (typically at lunch or dinner), but is sometimes eaten as cold leftovers for breakfast.