Tanuja was born in a Marathi family to filmmaker Kumarsen Samarth and actress Shobhna Samarth. She has three sisters, including actress Nutan and one brother. Her grandmother, Rattan Bai, and cousin Nalini Jaywant were also actresses. Tanuja's parents parted amicably while she was still a child, and Shobhana became linked to actor Motilal. Shobhana produced debut films for Tanuja and her older sister, Nutan. Her two other sisters are; Chatura, an artist, and Reshma, and her brother is Jaideep, none of whom took to acting.

 

Tanuja married filmmaker Shomu Mukherjee in 1973. The couple has two daughters, actresses Kajol and Tanisha. Kajol is married to actor Ajay Devgan. Shomu died on 10 April 2008 from a heart attack, aged 64. Filmmakers Joy, Deb and Ram are her brothers-in-law. She is the aunt of actors Mohnish Behl, Rani, and Sharbani, and director Ayan Mukherjee.