[1][2] "AOII," and "Alpha O," the familiar names of the fraternity,[3] is open to women regardless of ethnicity, religion or socio-economic background,[4] with over 140 active collegiate chapters and 159 active alumnae chapters in Canada and the U.S.A.[5][6] The fraternity is headquartered in Brentwood, Tennessee, and is a member of the National Panhellenic Conference.

[7] The sorority was founded January 2, 1897, at Barnard College by four women: Jessie Wallace Hughan, Helen St. Clair Mullan, Elizabeth Heywood Wyman, and Stella George Stern Perry.

[1][2] National expansion began in 1898 with the founding of Pi chapter at Sophie Newcomb College, now part of Tulane University, in New Orleans.

[10] In 1999, the fraternity's national council voted to establish AOII Properties, a branch which manages individual chapter housing, including safety, finances, and maintenance.

The subsidiary was then officially formed in 2001 but did not begin to transfer local housing contracts to national corporation control until 2009.

[14] The funds also support conference speakers, training events, and personal development programs for members.

Stuffed panda bears are collected each year to give to children attending Arthritis Foundation camps and conferences.

"[10] Individual chapters hold their own SOA events which vary from bowling tournaments to pageants to barbecues with funds going to AOII Foundation specifically for arthritis research.