The study is an attempt to investigate effect of home environment and school environment on personality development and academic achievement of secondary school students. The objectives of the study were, to investigate the effect of Home environment on Personality development and academic achievement of students, to explore the effect of school environment on Personality development and academic achievement of students, to find out the combined the effect of home environment and school environment on personality development and academic achievement of students; and to compare the relationship of home environment and school environment with personality development and academic achievement for different categories of students. A self reporting survey research design was adopted to conduct this research. Four research instruments comprising of home environment, school environment, relationship of staff members at school and personality inventory were used to collect data from students. Information about the academic achievement of the students was obtained by collecting their 9th grade result from Gazette book of Board of intermediate and Secondary Education (BISE) Abbottabad, 2013. Mean, Standard Deviation, Percentile, Multiple Regression Model, and Carl Pearson Correlation Coefficient was used to analyze the collected data. Major findings of study revealed that there were variations in terms of effect of home environment and school environment on Five Big Factors of personality and academic achievement of secondary school students. It was also found that home environment and school environment collectively affect the Five Big Factors of personality as well as academic achievement of secondary school students. On the basis of findings it was recommended that there is a need to train parents and teachers about their role in shaping personality and better academic achievement of secondary school students. It was also recommended that parental awareness about the provision of conducive home environment may be promoted through different measures. Conducive school environment in terms of teachers’ awareness about their role in balanced development of personality and academic achievement of students may be provided through different measures like provision of in service training, arrangement of seminars and workshops, and guidance and counseling centers at schools.