This policy brief outlines how the No Child Left Behind Act (NCLB) relates to high schools: (1) States must set adequate yearly progress (AYP) objectives (steadily increasing test scores and graduation rates) to ensure 100 percent of high school students achieve at proficient levels by spring 2014; (2) States must include high school graduation rates in the AYP objectives for high schools; (3) States must comply with the understanding of graduation rates, defined as the percentage of students who graduate from high school with a regular diploma in the standard number of years. As a result, states may no longer include recipients of general educational development (GED) certificates or alternative diplomas in their graduation rates; (4) All high school teachers who teach core subjects should have met the state's "highly qualified" requirement by the end of the 2005-2006 school year; and (5) Annually test (in the subjects of reading, math, and, eventually, science (by 2007-2008)) all high school students in at least one grade, including limited English-proficient students and students with disabilities, providing appropriate accommodations when necessary. (Contains 21 footnotes.) [This publication was produced by the National High School Center at the American Institutes for Research in collaboration with Learning Point Associates, MDRC, the National Center for Educational Accountability, the National Dropout Prevention Center/Network, the National Dropout Prevention Center for Students with Disabilities, and WestEd.]