Bhajan refers to any devotional song with a religious theme or spiritual ideas, specifically among Dharmic religions, in any language. The term bhajanam (Sanskrit: भजनम्) means reverence and originates from the root word bhaj (Sanskrit: भज्), which means to revere, as in 'Bhaja Govindam' (Revere Govinda). The term bhajana also means sharing.

The term bhajan is also commonly used to refer a group event, with one or more lead singers, accompanied with music, and sometimes dancing. Normally, bhajans are accompanied by percussion instruments such as tabla, dholak or a tambourine. Handheld small cymbals (kartals) are also commonly used to maintain the beat. A bhajan may be sung in a temple, in a home, under a tree in the open, near a river bank or a place of historic significance.

Having no prescribed form, or set rules, bhajans are normally lyrical and based on melodic ragas. It belongs to a genre of music and arts that developed during the Bhakti movement. It is found in the various traditions of Hinduism as well as Jainism. Within Hinduism, bhajans are particularly prevalent in Vaishnavism.

Ideas from scriptures, legendary epics, the teachings of saints and loving devotion to a deity are typical subjects in bhajans.

Bhajans have been widely composed anonymously and shared as a musical and arts tradition. Genres such as Nirguni, Gorakhanathi, Vallabhapanthi, Ashtachhap, Madhura-bhakti and the traditional South Indian form Sampradya Bhajan each have their own repertoire and methods of singing.