Mary Ann Gates (née Maxwell; July 5, 1929 – June 10, 1994) was an American banker, civic activist, non-profit executive, and schoolteacher.

[1] She served on the boards of various major corporations including the First Interstate Bank, Unigard Security Insurance Group, and Pacific Northwest Bell.

Gates also served for many years on the boards of several major corporations: First Interstate Bank of Washington; Unigard Security Insurance Group; Pacific Northwest Bell Telephone Company, which became USWEST Communications; and KIRO Incorporated.

In 1980, she discussed her son's company with John Opel, a fellow committee member, and the chairman of International Business Machines Corporation (IBM).

A few weeks later, IBM took a chance by hiring Microsoft, then a small software firm, to develop an operating system for its first personal computer.