Myzithra or Mizythra is a traditional unpasteurised Greek cheese made from the whey of sheep's, goats or cow's milk cheeses. It has been made in Greece for thousands of years and is believed to be the ancestor of all Greek whey cheeses. There are two forms of mizythra, fresh and dried.

Fresh mizythra is unsalted and consumed within a few days. In some parts of Greece, especially Crete, fresh mizythra is slightly fermented, until it becomes sour to taste. The result is a creamy, spreadable cheese called ‘xinomizythra’ or ‘sour mizythra’. The snowy white cheese with flavour similar to Ricotta Salata is used by Cretans to spread on paximadia or prepare tyropitas and kaltsounakia cheese pies.

Aged mizythra with rock hard texture and salty taste is called dried mizythra. In this form, mizythra is usually savored as a grating or cooking cheese over spaghettis.