Low cognitive growth is a concern in education. The contribution of family support, school environment, and peer influence on cognitive growth was examined. Diagnostic research design was applied.150 junior high school students selected through quota sampling were included in the study. Using multiple linear regression analysis, the result showed that family support, school environment, and peer influence have a moderately significant contribution (33.8%) to cognitive growth, supporting the Sociocultural Theory. Future studies may explore additional variables through qualitative research to explain the remaining 66.2% of cognitive growth variance, while educational leaders may implement programs that strengthen family support, school environment, and peer influence to improve cognitive growth