TIMSS 2015 is an international assessment of mathematics and science at fourth and eighth grades, conducted every four years since 1995. The 2015 assessment included 57 countries and 7 benchmarking entities, with over 580,000 students participating. The assessment included comprehensive frameworks for mathematics and science, with nearly 800 items, and a home questionnaire for fourth-grade students. TIMSS aims to help countries improve teaching and learning in mathematics and science by providing data on students' home, school, and classroom contexts. TIMSS 2015 results are presented separately for mathematics and science, with detailed information on student achievement, trends, and comparisons between countries. The assessment also includes TIMSS Advanced 2015, which focuses on advanced mathematics and physics for students in their final year of secondary school. The results show that East Asian countries like Singapore, Hong Kong, and South Korea performed well in mathematics at the fourth grade. Trends indicate improvements in mathematics achievement in many countries over time, with some countries showing significant gains. Boys generally outperformed girls in mathematics in more countries than girls did, though there were also countries where girls performed better. The assessment also examined achievement at different international benchmarks, with results showing variations in performance across countries. TIMSS 2015 also analyzed achievement in content and cognitive domains, with some countries showing strengths in specific areas. The assessment emphasized the importance of home environment support for learning, with some countries showing increases in home resources for learning between 2011 and 2015. Overall, TIMSS 2015 provided valuable insights into international trends in mathematics education and highlighted the importance of policy and context in student achievement.TIMSS 2015 is an international assessment of mathematics and science at fourth and eighth grades, conducted every four years since 1995. The 2015 assessment included 57 countries and 7 benchmarking entities, with over 580,000 students participating. The assessment included comprehensive frameworks for mathematics and science, with nearly 800 items, and a home questionnaire for fourth-grade students. TIMSS aims to help countries improve teaching and learning in mathematics and science by providing data on students' home, school, and classroom contexts. TIMSS 2015 results are presented separately for mathematics and science, with detailed information on student achievement, trends, and comparisons between countries. The assessment also includes TIMSS Advanced 2015, which focuses on advanced mathematics and physics for students in their final year of secondary school. The results show that East Asian countries like Singapore, Hong Kong, and South Korea performed well in mathematics at the fourth grade. Trends indicate improvements in mathematics achievement in many countries over time, with some countries showing significant gains. Boys generally outperformed girls in mathematics in more countries than girls did, though there were also countries where girls performed better. The assessment also examined achievement at different international benchmarks, with results showing variations in performance across countries. TIMSS 2015 also analyzed achievement in content and cognitive domains, with some countries showing strengths in specific areas. The assessment emphasized the importance of home environment support for learning, with some countries showing increases in home resources for learning between 2011 and 2015. Overall, TIMSS 2015 provided valuable insights into international trends in mathematics education and highlighted the importance of policy and context in student achievement.