Background <p>This study investigates the factors associated with eighth-grade mathematics achievement in Ghana, addressing the research gap by comparing student- and school-level influences. Given the persistently low mathematics performance in Ghana and sub-Saharan Africa, understanding these factors is critical for improving educational outcomes in the region.</p> Methods <p>Using data from the 2011 Trends in International Mathematics and Science Study (TIMSS), a two-level hierarchical linear model was used to analyse the mathematics achievement of 7323 students nested within 161 schools. Student-level variables included confidence, enjoyment, the value of mathematics, and educational expectations. School-level variables included discipline and safety, orderly environments, and emphasis on academic success.</p> Results <p>The analysis revealed that 40.71% of the variance in mathematics achievement was between schools, while 59.29% was attributable to individual students. At the student level, enjoyment of mathematics (β = 24.30, <i>p</i> &lt; .001) was the strongest positive predictor. At the school level, principals’ perceptions of discipline and safety (β = 31.15, <i>p</i> &lt; .001) were the most significant positive predictors of achievement.</p> Conclusion <p>Mathematics achievement in Ghana is associated with both students’ attitudes and the school environment. Enhancing students’ enjoyment and confidence in mathematics, alongside fostering disciplined, safe, and academically focused schools, is essential for improving students’ performance.</p>