Was born at Amritsar on 10 February 1931, the daughter of the famous Akali leader, Master Tara Singh. She was educated at Khalsa College, Amritsar, Panjab University, Chandigarh, and Camp College, New Delhi, and attained the degrees of M.A. (Philosophy), B.T. (Bachelor of Teaching) and Ph.D. (Philosophy). Her doctoral thesis was on "The Sikh Concept of the Godhead." She taught at Khalsa College, Amritsar, for one year during 1958-59, but left teaching to enter journalism and politics. She edited for three years the Punjabi daily Parbhat published simultaneously from Jalandhar and Delhi, and the monthly Sant Sipahi from Amritsar. She was president of the Istri Akali Dal, women's wing of the Shiromani Akali Dal, and was also active in the fields of education and social welfare. She was a member of the New Delhi Municipal Committee for two years from 1977 to 1979 during which period she chaired its social welfare subcommittee. She had also been a member of the Delhi Sikh Gurdwara Management Committee since 1975, and was a co-opted founder-member of the Sikh Education Society (Punjab) which ran Khalsa colleges at Qadiah, Bahga, Chandigarh and Sathiala. She also served for two years as a member of the Court of the Delhi University. She was a member of the National Committee on Women and the Advisory Committee of the Amritsar Municipal Corporation.

In April 1978, Dr Rajinder Kaur was elected to the Rajya Sabha, the upper house of Indian Parliament. In 1980, she participated in a seminar for Religion and Philosophy held at Wembley Conference Centre, London, and in 1982 she attended World Conference of Religious Workers on Disarmament in Moscow.

Dr Rajinder Kaur fell at Bathinda to the bullets of unidentified assassins on 5 February 1989.