This report presents results of the 2009 National Assessment of Educational Progress (NAEP) in reading and mathematics at grade 12. Results for students in the nation and, for the first time, in the 11 states that volunteered to participate in the 2009 state pilot program are reported as average scores and as percentages of students performing at or above three achievement levels: Basic, Proficient, and Advanced. Results for student demographic groups (e.g., race/ethnicity, gender, and highest level of parental education) are included, as well as sample assessment questions with examples of student responses. The Technical Notes and appendix tables provide information on NAEP samples, school and student participation rates, the exclusion and accommodation rates of students with disabilities and English language learners, and additional state-level results. Nationally representative samples of twelfth-graders from 1,670 public and private schools across the nation participated in the 2009 National Assessment of Educational Progress (NAEP). Approximately 52,000 students were assessed in reading, and 49,000 students were assessed in mathematics. National reading results from the 2009 assessment are compared to results from five earlier assessment years going back to 1992. The 2009 mathematics results are compared to those from 2005 when a change in the mathematics framework for the assessment necessitated a new trend line for that subject at grade 12. Highlights of the national results in 2009 show that the overall average reading score for twelfth-graders was 2 points higher than in 2005, but 4 points lower than in 1992. There were no significant changes from 1992 to 2009 in the reading score gaps between White and Black students or between White and Hispanic students. In mathematics, the overall average score was 3 points higher in 2009 than in 2005. There was no significant change from 2005 in the mathematics score gaps between White and Black students or between White and Hispanic students. In the 11 participating states, average reading scores in seven states were higher than the score for the nation, and scores for three states were lower. In mathematics, the average scores for six states were higher than the nation, and scores for three states were lower. (Contains 29 tables and 24 figures.)