Mathematics anxiety is an important psychological factor that can influence students’ learning, classroom participation, confidence, and academic performance in mathematics. The present quantitative study was conducted to examine the level of mathematics anxiety among secondary school students and to investigate its relationship with academic achievement in mathematics. A descriptive survey research design was adopted. The study proposed a sample of 175 secondary school students studying in Classes IX, selected through stratified random sampling from selected schools. Mathematics anxiety was measured using a structured Mathematics Anxiety Scale, while academic achievement was assessed through students’ mathematics examination scores. Descriptive statistics, independent-samples t-test, and Pearson’s product-moment correlation were proposed for data analysis. The illustrative findings indicate that mathematics anxiety has a significant negative relationship with academic achievement. Students with higher mathematics anxiety tend to obtain lower mathematics achievement scores. The findings have important implications for mathematics teachers, school authorities, counsellors, parents, and educational policymakers.