Between 1900 and 1920, enrollment by women increased on college campuses across the country.
In 1919, for the first time, fifty women were on a waiting list for rooms in McMillan Hall. In 1924, the alumni news announced: "A campaign for a women's building ... is now in progress under the direction of the young women of the University, assisted by the alumnae and the Woman's Faculty Club." The students, led by Miss Peyton Hawes raised $1,000 at a rummage sale, $250 at a bridge party, $300 from a carnival, and $750 selling hot dogs. By January, 1925, donations from sororities, alums, faculty, students, and Woman's Club members reached $40,000 towards a new building.
Soon students realized they would need to raise an additional $100,000 for a larger building. Half came from community donations, and the remainder was a loan from the University, paid back with $2.50 dues added to women's tuition rates. The University had earlier provided a similar loan-payback plan to men students for Fraternity Row.
The Women's Building formally opened November 15, 1928.
In 1979, at the Women’s Building rededication,
Chancellor William H. Danforth remarked:
“We feel the time has come to associate [the Women’s Building] with the name of a woman who devoted her bountiful intelligence and energy to furthering the education of women, a woman who in her own activities represented the finest qualities of womanhood, in fact, of humankind: wisdom, compassion, concern for the betterment of society. The woman we honor is Ann Whitney Olin, Mrs. Spencer T. Olin.”