This study used a multivariate analysis design to investigate sex difference in the performance on literary skills among 473 pupils in primary schools in Tanzania. The study inquired whether there would be sex difference in the total performance on literary skills; and whether the difference in the three contents of literary skills (writing, reading, and numeracy) would be significant when age, type of pre-school attended, and duration of stay at pre-primary school are controlled. Results indicated mean differences between males and females with females being favored. Further analysis led to interpretation that the nature of such observed sex differences in the performance on literary skills among the pupils across grades one, two, and three do not emanate from sex (being a male or female) itself, but probably from the skills obtained in the type of pre-primary school one attended. Practical and theoretical implications are thoroughly discussed.