Abstract:The Third International Mathematics and Science Study (TIMSS) is the largest and most comprehensive comparative study of education ever undertaken. It was conducted in 1995 with the participation of more than 40 countries. The wealth of data made available by TIMSS has led to many secondary studies of educational systems around the world. One such study was “Effective Schools in Science and Mathematics”. This paper is based on the data and findings of that study where the characteristics of schools and, in turn, classrooms in Singapore with high performance in mathematics at the eighth grade level (secondary two) are examined. Among the 14 predictors of grade 8 mathematics achievement, only six were found to be significant for Singapore. These were associated with homework, classroom environment, students’ conduct and future aspirations, and the teacher.