<p dir="ltr">This dataset originates from a cross-sectional quantitative study conducted with 2,508 high school students from 13 public urban institutions in Imbabura, Ecuador. The objective was to examine whether mathematics anxiety varies across gender, age, and ethnicity. The Mathematics Attitude Scale (MAS) was administered to measure levels of anxiety toward mathematical tasks. The analyses revealed statistically significant differences: female students presented higher mathematics anxiety than male students; older students (18–19 years) showed elevated anxiety compared to younger peers (14–15 years); and ethnic group comparisons indicated higher levels among Afro-descendant students relative to Mestizo and White students. Overall, the dataset supports research examining socio-demographic disparities in mathematics anxiety and highlights the relevance of culturally and developmentally informed educational interventions.</p>