The United States Association for Young Physicists Tournaments (USAYPT) held its 4th annual US Invitational Young Physicists Tournament 4-5 February 2011 at the Institute for Science Education, Oak Ridge Associated Universities, Oak Ridge, Tennessee.  This year's teams were from the Harker School, San Jose, California; the Madeira School, McLean, Virginia; Oak Ridge High School, Oak Ridge, Tennessee; Rye Country Day School, Rye, New York; the Vistamar School, El Segundo, California; and the Woodberry Forest School, Woodberry Forest, Virginia.