Bush was hospitalized early last year when her husband, former President George H.W. Bush, was admitted for treatment of a case of viral bronchitis.
The Bushes had six children, including former President George W. Bush, 2016 Republican presidential candidate Jeb Bush and Robin Bush, who died as a child.
Barbara Bush was born June 8, 1925 in New York City.
Related: Photos: Barbara Bush through the years
She married George H.W. Bush in 1945, making theirs the longest marriage of any presidential couple in American history. Barbara Bush supported her husband throughout his political career, including his time as a congressional representative from Texas, as vice president and as the 41st president of the United States.
Barbara Bush founded the Barbara Bush Foundation for Family Literacy in 1989 with the goal of empowering families through literacy.
Bush is survived by her husband, George H.W. Bush, five children, 17 grandchildren and seven great grandchildren.