Women in Defense began in the fall of 1979 as the brainchild of six or seven women who met for dinner at the conclusion of a major trade association conference.  At that time, they discussed the idea of starting an informal network to assist participants--especially women and thus the organizational name--in expanding their knowledge of national security issues and of the national defense community in which they participated.

For a year, the entity did not have a formal name or methodology for achieving its objectives.  During that time, a small group of women worked to expand the organization and to increase the frequency and quality of its activities.  In the fall of 1980, the group sponsored a get-acquainted dinner.  From then until February 1981, the enlarged group devised an approach for organizing what would become Women In Defense.

In April 1981, the organization sponsored its first formal luncheon, featuring Mae Walterhouse of the Environmental Protection Agency.  Since June 1981, WID, as an organization, has grown, incorporated, added chapters, and conducted many professional development activities, including formal business luncheons and breakfasts featuring senior level personnel from the administrative and legislative branches of government and industry.

WID's continued growth led them to incorporation as a nonprofit 501(c)(6) organization, accomplished during the latter months of 1985.  The first annual meeting was held January 1986 where the first slate of officers nominated and elected in accordance with the charter.

In 1994 WID became an affiliate of the American Defense Preparedness Association, who merged with with National Security Industrial Association (NDIA) in March 1997.  Finally, in June 2004, WID became a full affiliate with NDIA.

At the beginning of 2009, WID had about 1900 members and continues to grow.