The TIMSS 2011 International Results in Mathematics summarizes fourth and eighth grade student achievement in each of the 63 countries and 14 benchmarking entities which participated in TIMSS 2011. The report includes trends in mathematics achievement over time for participants in the previous TIMSS 1995, 1999, 2003, and 2007 assessments, as well as student performance at the TIMSS International Benchmarks. Achievement results also are presented for mathematics content and cognitive domains. The Mathematics Report provides a rich array of information which describes the educational contexts for mathematics, including home environment support, students' backgrounds and attitudes toward mathematics, the mathematics curriculum, teachers' education and training, classroom characteristics and activities, and school contexts for mathematics learning and instruction.