This study aimed to investigate whether Thai high school students' perceived teacher support could enhance their reading ability through self-efficacy and sense of school belonging. The theoretical foundation of this study included the theory of social-motivational processes and social cognitive theory. Structural equation modeling was used for analysis and validation. The student questionnaire from the Programme for International Student Assessment (PISA) 2018 survey questions regarding teacher support, sense of school belonging, self-efficacy, and reading ability. The sample consisted of the data collected from the Thai students in the PISA 2018 survey, with an effective sample size totaling 7968. The research results of the overall model showed that the perceived teacher support of Thai high school students' had no direct effect on their reading ability, but their perceived teacher support had an indirect effect on reading ability through their self-efficacy and sense of school belonging. From the results can be seen that high school teachers in Thailand, in supporting and encouraging their students in learning, must simultaneously develop their perceived self-efficacy and sense of school belonging. Only thus can there be obvious help to their students' reading ability.