The international comparison of students' mathematics knowledge and competencies is an effective method of evaluating students' mathematics performance and developing policies to improve their achievements in mathematics. Trends in International Mathematics and Science Study (TIMSS) are among the most well-recognized international comparisons that provide valuable information about students' mathematics achievement in an international area. The results of TIMSS in the period of 1999 to 2011 in students' mathematics achievement, particularly in 8thgrade, shows that Singapore has had one of the best students' mathematics achievement. The present study, therefore, deeply analyzes the mathematics curriculum, and compare the mathematics textbooks (Secondary 1 & 2) with contents domain of TIMSS including Numbers, Algebra, Geometry, and Data and Chance (Statistics and Probability), to highlight the reasons for such a desirable mathematics achievement. Findings of the present study may offer valuable insights to mathematics educators and syllabus designers.