The bhakti literature is the most important development of the medieval period. Krishna and Rama, the two main incarnations of the great god Vishnu, began to be worshipped widely. Many temples were built for them, and their worshippers formed a number of different sects, each one following a particular religious teacher. Much bhakti literature was written in the form of hymns, still sung today. These hymns praised the deities and their deeds, or humbly requested their help.

Bhakti poetry was an important influence in the development of regional languages because it emphasized people's everyday speech, rejecting the elite tradition of Sanskrit. Bhakti also challenged the caste system as many of its poets were from the lower castes and a common theme of the poetry is that God is within every human being.

Some of the earliest bhakti poetry was written in Tamil. From the A.D. 900's, Kannada became an important influence, with devotional literature such as the Vachanas (sayings) of the saints of various Hindu sects. Famous Kannada poets of the medieval period include Basavanna and Allama Prabhu.

The next language to adopt bhakti was Marathi, the most important poet being Gyaneswar (1200's). Other Marathi poets were Eknath and Tuka Ram. In Gujarati, prominent poets were Narsi Mehta and Premananda. Other languages to follow the tradition were Kashmiri, Bengali, Assamese, Manipuri, Oriya, and early variants of Hindi. Another kind of bhakti is found in the Sant tradition, which believes in one omnipresent God. Bhakti became a great platform for Hindu-Muslim unity.

Women poets of bhakti.   The contribution of women writers in different languages deserves special attention. Lal Ded (1320-1384) was a Muslim poet from Kashmir. She wrote in the Sant tradition. Mira Bai (1500's) wrote in Gujarati, Rajasthani, and Hindi. She wrote songs of Krishna in a voice of longing, expressing the pain of separation from the god she loved as a husband. Avvayyar, writing in Tamil, and Akkamahadevi, writing in Kannada, wrote about the position of women in society.