A quesadilla or sometimes specifically a cheese quesadilla, is a Mexican dish and type of taco, consisting of a tortilla that is filled primarily with cheese, and sometimes meats, beans, vegetables, and spices, and then cooked on a griddle. Traditionally, a corn tortilla is used, but it can also be made with a flour tortilla, particularly in northern Mexico and the United States.

A full quesadilla is made with two tortillas that hold a layer of cheese between them. A half is a single tortilla that has been filled with cheese and folded into a half-moon shape. A quick version of the quesadilla, the cheese tortilla, is microwaved and often served to children.