During Sunshine Week, news organizations, civic and watchdog groups, libraries, nonprofits, schools and other participants engage public discussion on the importance of open government through news and feature articles and opinion columns; social media campaigns; infographics; editorial cartoons; public service advertising; public seminars and online or in-person forums.

The purpose of the week is to highlight the fact that "government functions best when it operates in the open.

The following year, the idea of a national Sunshine Sunday was raised at an American Society of Newspaper Editors Freedom of Information summit.

In the planning stages, it was decided that the initiative needed to be more than a single Sunday, and Sunshine Week was established in March 2005 by the American Society of Newspaper Editors, with funding from the John S. and James L. Knight Foundation.The first nationwide Sunshine Week took place March 13–19, 2005.

In December 2023, NLA placed Sunshine Week with the Brechner FOI Project at the University of Florida College of Journalism and Communications.