This paper examines the inequality in secondary school attainment and its determinants across gender, caste, and ethnic group in rural Nepal. Using the primary data from a questionnaire survey, a series of interviews, and school observations, this study found that girls' school attainment is significantly lower than that of boys'. Similarly, "Dalit" (the lowest caste) and "Janajati" (indigenous, disadvantaged ethnic groups) students' school attainment is considerably lower than that of "Brahman and Chhetri" (high caste and privileged ethnic groups) students. Furthermore, the regression analysis using the education production function approach revealed that household chores, father's education, land sufficiency, student/teacher ratio, and local caste/ethnic composition are significant determinants affecting students' school attainment. However, students' desired level of education and the number of siblings they have were insignificant in this study. The results indicate that policy for inclusive education should be based on the local socio-cultural environment, especially with regard to the caste/ethnic composition of the local community.