Persian literature comprises oral compositions and written texts in the Persian language and is one of the world's oldest literatures. It spans over two-and-a-half millennia. Its sources have been within Greater Iran including present-day Iran, Iraq, Afghanistan, the Caucasus, and Turkey, regions of Central Asia, South Asia and the Balkans where the Persian language has historically been either the native or official language. For example, Rumi, one of the best-loved Persian poets, born in Balkh or Wakhsh, wrote in Persian and lived in Konya, at that time the capital of the Seljuks in Anatolia. The Ghaznavids conquered large territories in Central and South Asia and adopted Persian as their court language. There is thus Persian literature from Iran, Mesopotamia, Azerbaijan, the wider Caucasus, Turkey, Pakistan, Bangladesh, India, Tajikistan and other parts of Central Asia, as well as the Balkans. Not all Persian literature is written in Persian, as some consider works written by ethnic Persians or Iranians in other languages, such as Greek and Arabic, to be included. At the same time, not all literature written in Persian is written by ethnic Persians or Iranians, as Turkic, Caucasian, Indic and Slavic poets and writers have also used the Persian language in the environment of Persianate cultures.

Persian, also known by its endonym Farsi or Parsi, is a Western Iranian language belonging to the Iranian branch of the Indo-Iranian subdivision of the Indo-European languages. Persian is a pluricentric language predominantly spoken and used officially within Iran, Afghanistan, and Tajikistan in three mutually intelligible standard varieties, respectively Iranian Persian, Dari Persian, and Tajiki Persian. It is also spoken natively in the Tajik variety by a significant population within Uzbekistan, as well as within other regions with a Persianate history in the cultural sphere of Greater Iran. It is written officially within Iran and Afghanistan in the Persian alphabet, a derivative of the Arabic script, and within Tajikistan in the Tajik alphabet, a derivative of the Cyrillic script.