This study aims to identify the factors that distinguish low-performing schools from high-performing schools in mathematics​ in Cambodia. Using quantitative research, the study analyzed student data from the Grade 6 National Learning Assessment (NLA) in 2021 through crosstab analysis. The findings revealed several variables that significantly influenced students’ mathematics performance between low- and high-performing schools, including students’ age, preschool attendance, grade repetition, absenteeism, attitude toward school, social economic status and parents’ education and occupation. In addition, in high-performing schools, a greater proportion of students are of the appropriate age, have attended preschool, demonstrate a positive attitude toward school, and have parents with at least a 7th-grade education. Their parents are employed as salespeople, government officials, or company employees. In contrast, in low-performing schools, more students tend to be absent, repeat grades, and have parents who only completed 6th-grade. These parents are more likely to work as farmers, fishermen, or laborers. Practical and conceptual discussions were made to serve as the basis for recommendations to narrow the gap in mathematics performance between the two groups of schools.