The article discusses the diversity and equity issues behind the learning outcomes of mathematics in the pre-COVID context in Nepal. The article intends to give a baseline for the further studies on the effect of COVID-19 pandemic in the educational realm. Datasets from the national assessment of student achievement in Nepal at grades 3 and 5 and grade 8 are reanalyzed based on socioeconomic status (SES), gender, caste-ethnicity, language, and geographical variables. In Nepal, where the society is customarily highly structured, gender-biased, and poverty-driven, SES influences remarkably in mathematics achievement. The datasets show notable relationships between SES and mathematics achievement (r = 0.35, 0.27 and 0.30 in grade 3, 5 and 8, respectively). In lower grades, the difference between the highest and lowest SES in the achievement of girls is wider than boys and it is reverse in grade 8. Nepali speakers had high scores when they had high SES but, when SES was very low, the non-Nepali speakers performed better in all grades. The advantageous castes tended to always perform higher irrespective of their level of SES. Nevertheless, it is difficult to know with certainty when average and marginalized caste/ethnic groups perform better.