Sefi Atta was born in Lagos, Nigeria, in January 1964, to a family of five children. Her father Abdul-Aziz Atta was the Secretary to Federal Government and Head of the Civil Service until his death in 1972, and she was raised by her mother Iyabo Atta.

She attended Queen's College, Lagos, and Millfield School in England. In 1985, she graduated from Birmingham University. She qualified as a chartered accountant in England and as CPA in the United States. She is married to Gboyega Ransome-Kuti, a medical doctor, and son of Olikoye Ransome-Kuti. They have one daughter.

Sefi's Lagos-based production company Atta Girl supports Care to Read, a program she initiated to earn funds for legitimate charities through staged readings.

She currently divides her time between Nigeria, England and the United States.