This book is about the difference in learners' achievement in public and private primary schools in Tanzania. The main difference between private and public primary schools in Tanzania is the use of two different languages of instruction; where private primary schools use English as the language of instruction and public schools use Kiswahili. Three subjects namely Kiswahili, English and Mathematics were assessed to investigate the differences. The main issues discussed in this book are comparative analysis of learners' performance in English, Kiswahili and Mathematics in public and private primary schools. Moreover the book discusses the reasons for the differences in learners' achievement. Private primary schools are considered to be of better quality as the pupils' performance and achievement in general is good. One of the indicators that private primary schools prepare their pupils to do well in their PSLCE is the number of pupils who pass PSLCE. The target groups who can benefit from the book are policy makers, educationists within and outside Tanzania, parents, teachers and people who are interested to get information about the education system of the Mainland Tanzania.