This paper reports about a cross-national comparison of sixth-grade pupils’ performance in mathematics using the SACMEQ II data for Botswana, Lesotho, and Swaziland. Statistical analyses were done in order to explore the relationship between achievement in mathematics and factors such as gender, socio-economic status of pupils, location of the school, and access to mathematics textbooks. The results suggest, amongst other things, that Swazi sixth graders outperformed their Batswana and Basotho counterparts, with the latter showing lowest average scores in mathematics. Except for Lesotho, pupils from families with high socio-economic status outperformed their counterparts from low socio-economic status in Botswana and Swaziland. Furthermore, in all the three countries, pupils from the schools located in large cities out-performed their counterparts from small towns and rural areas; with the latter showing the lowest average scores in mathematics. Additionally, the socio-economic level of pupils tended to affect their achievement in mathematics differently depending on the location of the school. This paper examines some research and policy implications of the findings.