Formal Education has been recognized as a dynamic instrument of change in Nigeria and today there is increasing awareness and quest for secondary and higher education. However, under achievement especially in compulsory, core school subjects (Mathematics and English)in secondary school have been a problem. This problem has been traced to poor study habit and adjustment in schools. This book therefore addresses relationship among student adjustment, study habit and academic achievement with the aim of determining if student adjustment predicts achievement better than study habit. It considers a sample of 600 senior secondary students from 20 secondary schools drawn from the population of Secondary Schools in Kano State. Using Eze and Odo Student Adjustment Scale, Bakare Study Habit Inventory, Student Achievement Test in English and Mathematics and with the aid of descriptive statistics and multiple Regression Analysis, it was found that Student Adjustment is more related to academic achievement than study habit. The book is useful to School Counselors, Teachers Psychologist,School Proprietors, Parent, Researchers and Educationist.