Sistla Janaki (born 23 April 1938), popularly known as S. Janaki, is an Indian playback singer and occasional music-composer from Andhra Pradesh. She is referred to respectfully as “Janakiamma” and is one of the best-known playback singers in India. She has recorded nearly 48,000 songs in films, albums, TV and Radio including solos, duets and chorus songs in more than 17 languages including those native to India mainly in Kannada, Malayalam, Tamil, Telugu, Hindi, Odia, Bengali, Tulu, Urdu, Gujarati, Punjabi, Sindhi, Assamese, Konkani and also in languages such as English, Japanese, Latin, Arabic, German, Sinhala, French, Bangla, Russian and Chinese. Starting in 1957 with the Tamil film Vidhiyin Vilayattu, her career has spanned over six decades.

Janaki, who is fondly called “The Nightingale of South India”, has won four National Film Awards and 33 different State Film Awards. She is the recipient of an honorary doctorate from the University of Mysore, the Kalaimamani award from Government of Tamil Nadu and Karnataka Rajyotsava award from Government of Karnataka In 2013, she refused to accept Padma Bhushan, and pointed that it is too little and had come “too late” and that South Indian artists were not given their due recognition.

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. Yesudas and Dr. Rajkumar topped the charts across all the South Indian languages. She has sung in almost all the genres of songs. In October 2016, Janaki announced her retirement from singing for films and stage appearances. However, under pressure from the film fraternity, she made a comeback for the Tamil film Pannadi in 2018.