Kasseri (Greek Κασέρι; or in Turkish kaşer, kaşar) is a medium-hard pale yellow Greek cheese made from unpasteurized sheep milk with very little, if any, goat's milk mixed in. The cheese is found in Greece, Bulgaria and Turkey. An alternative way of making the cheese uses cow-milk.
It is a soft textured, stringy rather than crumbly, chewy, hard-rind cheese and belongs to the pasta filata family of cheeses, like Provolone or Mozzarella. The use of fresh unpasteurized milk is necessary to obtain the correct flavor and texture, and aging of at least four months is required for the development of flavor. Aged kasseri faintly resembles Parmesan or Asiago but is not as creamy.