Which Mexican cheese is known for its stringy texture and is used on quesadillas?

Oaxaca cheese is the Mexican cheese known for its stringy texture and frequent use in quesadillas. It is also called quesillo or queso de hebra, names that refer to its distinctive pulled, thread-like form.

The cheese originated in the state of Oaxaca. Its production uses a stretched-curd technique similar to the pasta filata method used for mozzarella. Cheesemakers stretch the warm curd into long ribbons, wind them into ropes, and coil those ropes into compact balls. This gives Oaxaca cheese a soft, springy texture and excellent melting ability.

In quesadillas, the cheese melts into a smooth, stretchy filling. It is also used in empanadas, tlayudas, and other Mexican dishes. Asadero is a common mix-up because it is another meltable Mexican cheese with a somewhat similar texture, but it is associated especially with northern Mexico and is not the canonical answer to this question. Cotija and queso fresco are generally crumbly cheeses used as toppings rather than stringy melting cheeses.