The purpose of the study was to find out association between family social capital and academic achievement of the secondary school students. The study was confined to (632) public secondary schools (male and female, urban and rural) in Multan division. The sample of the study was 886 urban students (boys), 785 urban students (girls), 803 rural students (boys) and 337 rural students (girls).The total sample comprised of 2811 students of 9th class. After reviewing the related literature, a hypothetical framework was developed to measure the family social capital of secondary school students. A self-inventory of five point rating scale was developed for the students of 9th class. There were twenty-seven statements about students’ demography. The self-inventory was consisted of sixty statements. The self-inventory was divided into six components: education level of the family, family-child relationships, familial monitoring, family expectations, parenting style (attitude) and parent-school association. The validation of research instrument was checked by five research-experts in education. The reliability of research instrument was .89. The factor loading of components of family social capital was determined by using Component Factor Analysis (Exploratory Factor Analysis). Sampling Adequacy was measured by using KMO (Kaiser-Meyer-Olkin) of Sampling Adequacy that was .92(marvelous). Academic achievement of the students were determined from the marks of SSC Examinations year 2015. Data collected from the students were analyzed on SPSS-20.Crosstabulation, Chi-square and tests of significance were applied to determine the association between family social capital and academic achievement of secondary school students. Through this study, it was found that most of the components of family social capital e.g. education level of the family, family-child relationships, familial monitoring, parenting style and parent-school association and demographic variables e.g. monthly income of a family, property of a family, mobile phone (possessing by the students), doing work for earning after school time by the students, had association with students’ academic achievement. Only a few variables e.g. family size, family structure and family order had no association with students’ academic achievement. From this study, it was concluded that, family social capital was closely related to academic achievement of secondary school students. It means that, if the family social capital of a student was greater, he/she achieved good grades and vice versa. From this study, it was concluded that, if the education level of a family was higher, then their children got good grades. From this study, it was determined that if the parents establish close relationships with their children because these relationships develop the confidence in children. As a result, they will get good grades. From this study, it was concluded that, if the parents monitor all the activities of their children to determine their problems and try their best to solve these problems. Their children will achieve good grades. From this study, it was also concluded that if the parents make their attitude democratic in their home. This attitude will develop the personality of the children as a whole. They would study whole-heartedly and, as a result, they will get good marks. From this study, it was concluded that, mobile phone spoiled the children (boys and girls). So the parents should not give them mobile phone although they afford to purchase it for them. Parents should not let the children to work for earning after school time because this study showed that this work had bad effects on students’ results.