The National Advisory Committee for Aeronautics (NACA) was a U.S. federal agency founded on March 3, 1915 to undertake, promote, and institutionalize aeronautical research. On October 1, 1958 the agency was dissolved, and its assets and personnel transferred to the newly created National Aeronautics and Space Administration (NASA). NACA was pronounced as individual letters, rather than as an acronym.

The name remains familiar in the automotive world for the NACA duct, a type of air intake, or to those in the aircraft industry, as several series of NACA airfoils and NACA cowling are still being used in new design.