NIAC

NIAC may refer to:


 * NASA Institute for Advanced Concepts, an external NASA program that closed in 2007
 * NASA Innovative Advanced Concepts, an internal NASA program that began in 2010
 * National Immunisation Advisory Committee, an immunization advisory committee in Ireland
 * National Indoor Athletics Centre, an indoor track and field athletics sports venue in Cardiff, Wales
 * National Infrastructure Advisory Council, a council of the United States Department of Homeland Security
 * National Infrastructure Assurance Council, replaced by the National Infrastructure Advisory Council as of the signing of U.S. Executive Order 13231
 * National Iranian American Council, an association of Iranian-Americans
 * Nationwide Investigation Advisory Committee a committee within the United States Department of Justice (DOJ)
 * Nebraska Intercollegiate Athletic Conference or Nebraska-Iowa Athletic Conference, former names of the Great Plains Athletic Conference, American college athletic conference
 * Non-International Armed Conflict, a type of conflict defined in International Humanitarian Law
 * Nonprofits Insurance Alliance of California, the first and largest organization in the Nonprofits Insurance Alliance Group
 * Northern Ireland Assembly Commission, the corporate body of the Northern Ireland Assembly
 * Northern Indiana Athletic Conference, an IHSAA Athletic Conference based in South Bend, Indiana.
 * Northern Intercollegiate Athletic Conference, a college athletic conference in North Dakota, Minnesota and Manitoba
 * Nuclear Industry Assessment Committee, an organization that shares auditing services among its members