Leela Roy (Nag) was born on October 2nd, 1900 into an upper middle class family in Sylhet. Her parents were of Raibahadur Girishchandra Nag and Kunjalata Nag. From her childhood she was aware of the social problems and the hardships of the people of India under British rule. In 1921 Leela Roy (Nag) graduated in English from the Bethune College, Calcutta and got the Padmabati gold medal. In 1923 she received her M.A in English from the University of Dhaka and was the first woman to be admitted to that University. Her interest in social works reflected on many cases when she was a student. After completing education Leela Roy (Nag) completely dedicated herself into the social welfare. She was deeply moved by poor condition and low status of the women in the society. She established a girl`s school in Dhaka. Later, in 1928 she founded schools like Nari Siksha Mandir, Siksha Bhawan and Siksha Niketon. She realized that the girls needed an economical freedom to raise their voice. Leela Roy (Nag) assisted the local girls to take vocational training and organized Deepali Exhibition to sell the product made by the girls.

Leela Roy (Nag) founded "Dipali Shongho" for providing training to the girls so that they could join in the Indian freedom struggle. Pritilata Waddedar took traning from this organization.In 1931 she started publishing a journal named Jayasree .The name of this magazine was given by Rabindranath Tagore.It was the first magazine edited entirely by women and all the writers were also woman. For her active participation in the Civil Disobedience Movement British Government imprisoned her. Leela Roy (Nag) came close contact with Subhas Chandra Bose. She was selected as the member of the Women`s Sub-committee of the National Planning Committee of Congress, which was founded by Subhaschandra Bose. In 1939 Leela Roy (Nag) got married to Anilchandra Roy who was a well-known nationalist. In 1941 she established Unity Board and National Service Brigade during the communal riot of Dhaka. In 1942, Leela Roy (Nag) took part in the Quit India Movement .At that time Government banned her magazine. In 1946, she was released and selected as the member of the Constituent Assembly of India. During riots of Noakhali in 1946 Leela Roy (Nag) went there before Gandhiji and served for the distressed and affected people. She established relief camp and saved 400 women. During partition, Leela Roy (Nag) opened several centres in Calcutta to assist refugees from East Bengal. She also established the Minority Welfare Central Committee to arrange relief camps for the refugees. In 1946 she established the Jatiya Mahila Sanghati in Calcutta to help the women economically. Leela Roy (Nag) died in 1970.