Barbara Bush was the matriarchal figure of a political dynasty that included two presidents - her husband George HW Bush and son George W Bush.
Mrs Bush, who was first lady from 1989 to 1993, had been in failing health for some time and had declined further medical treatment.
Her husband, at 93, is the longest-lived US president. Their son, George, was elected in 2000 and served two terms as the nation's 43rd president.
Mrs Bush was also the mother of Jeb Bush, who served as governor of Florida from 1999 to 2007 and unsuccessfully ran for the White House in 2016.
As first lady, Mrs Bush went beyond the traditional role of a political spouse, founding the Barbara Bush Foundation for Family Literacy to help parents and children from disadvantaged communities to read and write.
She was a fierce advocate of civil rights and went against many of her husband's Republican party supporters with her more liberal view on abortion rights.
Mrs Bush was known for her snow-white hair and was dubbed "The Silver Fox" by her family.
She once dismissed speculation that she had influenced her husband during his time in the White House, saying: "I don't fool around with his office and he doesn't fool around with my household."
She met her future husband in 1941 at a Christmas party in Connecticut and the couple celebrated their 73rd wedding anniversary in January this year.
They had six children including a daughter, Robin, who died of leukaemia aged three in 1953.
As well as George and Jeb, the other Bush children are Neil, Marvin and Dorothy.