SUMMARY
Studies into the elements that influence students' academic progress have drawn the interest and concern of teachers, counsellors, psychologists, researchers, and school officials in Nigeria. The foundation of society is the family, which is generally understood as a couple raising their children or a group of individuals living under one roof and typically under one head. Every family is thought to want their children to do well in school. However, a lot of elements, such as economic pressure, lead families to lose interest in their children's academic endeavours. The study aimed to investigate the relationship between secondary school students' academic achievements and their family structure in Oyo State, Nigeria. A structured questionnaire was utilised for the study to collect data because it helped the researcher found to standardise data collection, categorise data for statistical analysis and collect data at a lower administrative cost. Descriptive and correlational approaches were also applied. Correlational design helps identify the relationship between two variables, while the descriptive design accurately describes the events as they actually occur. Therefore, it was possible to establish a connection between the type of family and the pupils' academic performance. One-way ANOVA was used as the statistical tool to analyse the data. This decision was taken after running the descriptive analysis of the dependent variables. According to the study's findings, family structure and their socioeconomic position, parenting, and upbringing affects pupils' academic achievements in secondary schools in Oyo State, Nigeria. Also, family structure affects parental support, class concentration, and the self-esteem of students. Additionally, there is a correlation between students' academic success in secondary schools in Oyo State, Nigeria and the family structure. The study findings indicate that the provision of basic needs (food, shelter, and clothing), mental wellbeing, adequate economic resources, harmony in the parents' relationship, and soundness of the parent-child relationship were significantly influencing the academic performance of students in secondary schools in Oyo State, Nigeria