The Northwest Association of Secondary and Higher Schools was formed as a voluntary organization on April 5, 1917, with a membership of 25 secondary schools and eight higher institutions in four Northwestern states. Over the decades, its membership expanded to more than 1,900 institutions, accrediting schools across Alaska, Idaho, Montana, Nevada, Oregon, Utah, and Washington.
In December 1974, the title of the organization was changed to the Northwest Association of Schools and Colleges. In 2001, it became the Northwest Association of Schools and of Colleges and Universities, and in 2004, the name was updated to the Northwest Association of Accredited Schools. In 2010, following a restructuring plan, the organization took its current form as the Northwest Accreditation Commission (NWAC).