Sistla Janaki is an Indian playback singer and occasional music composer from Andhra Pradesh. She is widely referred to as "Janaki Amma" and "Nightingale of South India". She is one of the best-known playback singers in India. She has recorded over 48,000 songs in films, albums, TV and Radio which includes solos, duets, chorus and title tracks in 17 languages including Kannada, Malayalam, Telugu, Tamil, Hindi, Sanskrit, Odia, Tulu, Urdu, Punjabi, Badaga, Bengali, Konkani and also in foreign languages such as English, Japanese, German and Sinhala; the highest number of songs in her career were in Kannada followed by Malayalam. Started in 1957 with the Tamil film Vidhiyin Vilayattu, her career has spanned over six decades. She is referred to as Gaana Kogile in Karnataka, Gaana Kokila in Telugu States and Isaikkuyil in Tamil Nadu. '''S. Janaki is widely acclaimed as a Queen of Expressions & Modulations in any language with nativity.''
Widely acclaimed as one of the most versatile singers, her association with singer S. P. Balasubrahmanyam and composer Ilaiyaraaja is most talked about. In the 1960s, 1970s and 1980s her duets with P. B. Srinivas, S. P. Balasubrahmanyam, K. J.