The International Association for the Evaluation of Educational Achievement's (IEA's) Trends in International Mathematics and Science Study (TIMSS) can reveal a great deal about national teaching cultures and policies. Changes in instructional practices over more than a decade may be studied from a cross-cultural perspective. Using teacher and student reports on the frequency of seven distinct practices, as assessed by TIMSS in 1995, 1999, 2003 and 2007, it is possible to identify a number of significant changes between adjacent time points for individual countries. Teaching practices seem to be shaped by national educational cultures or policies. While this brief does not identify the causes or effects of these changes, there is mixed evidence for global "mega-trends" in education, as discussed by researchers and policymakers. Constructivist pedagogy (working in groups, applying mathematical content to daily life) was boosted on a large scale during the mid-2000s. However, there is only limited support for a rise in assessment-based instruction and a shift from computational practice to problem-solving in mathematics. TIMSS evidence suggests a quest for systematic development of teaching practices, classroom cultures, and teacher quality at the national level.