In this paper, comparative analyses of pupils’ mathematics achievement were performed. Data analyzed consisted of about 42,000 pupils from 14 countries. The focus of the study was on learning environment and mathematics achievement in which variables such as class size, school location, classroom resources and whether or not pupils take extra tuition were analyzed and compared to pupils’ mathematics achievement across the countries that participated in the study. Mixed results were found on almost all variables explored. The only consistent finding across the countries was that pupils attending urban schools performed higher than those attending rural schools. Generally, pupils exhibited low achievement in mathematics; it is only in two countries where pupils obtained slightly over fifty percent of the total score. Gender differences in favor of girls were found in five out of 14 countries but the highest difference was in favor of girls. It is concluded that mathematics achievement is a complex phenomenon as many variables seem to affect it. Consequently, improving mathematics achievement would entail addressing these multiple factors simultaneously.