The objective of this study was to examine causal effects of four dimensions of social capital (i.e. family, school, peer, and community) on the psychosocial wellbeing of adolescents in the northeast region of Thailand. A survey research was employed to collect data from 1,142 adolescents and their parents living in three provinces; i.e. Udon Thani, Khonkean, and Nakhon Ratchasima. The Structural Equation Modeling (SEM) was used to analyze the surveyed data The findings showed that: only three dimensions of social capital; i.e. family (B=.37,p<.01) ...