This study was aimed at clarifying the position of environment and heredity in scholastic aptitude by investigating the role of family, educational, and economic factors in the scholastic aptitude of ninth-grade students. This applied study adopted a quantitative approach and a descriptive causal- comparative method in terms of data collection. The statistical population of the research included all 1,234,641 students in the ninth grade of the secondary schools in Iran in the academic year of 2020–2021. The sample size contained 11790 students selected through proportionate stratified random sampling. The data were collected using a 64-question Scholastic Aptitude Test and analyzed using descriptive statistics as well as the MANOVA using the SPSS 25 software. The research results showed that among the family factors, the mother's educational level; among the educational factors, the type of school and educational assistance classes; and among the economic factors, the family income, had a significant role in the students' scholastic aptitude (P < 0.05). Moreover, the linear combination of family factors and educational factors does not have a significant role in scholastic aptitude while the linear combination of economic factors has a significant role. In general, among family, economic, and educational factors, economic factors have a more significant role in scholastic aptitude.
