Literature indicates that teachers' technology integration is affected by internal (individual feeling) and external (support from schools) factors. How the two levels of factors affect continuous technology integration remains unclear. Drawing upon the organizational support theory, this study thus proposes a multilevel model to examine how factors at two levels--teacher and school--account for teachers' technology integration. In the model, teachers' technology integration is a teacher-level variable, while school support at the school level, refers to how well the school supports teachers. The model specifically investigates the serial mediating roles of teachers' perceived school support and ICT self-efficacy in the relationship between school support and teachers' technology integration. Large-scale data (297 schools and 8041 teachers) was collected for analysis. The multilevel mediation model was constructed and analyzed using a multilevel structural equation modeling (MSEM) approach. Key results from the analysis illuminate that school support can only impact teachers' technology integration when teachers' perceived school support acts as a mediator. Teachers' ICT self-efficacy also plays a partial mediation role between teachers' perceived school support and their technology integration. These findings validate the proposed model. They highlight teachers' unarticulated need for a supportive school environment and the crucial role of teachers' perceptions in translating school support into technology integration practices. In doing so, we make a contribution to the methodology for developing effective school support and cultivating appropriate teacher perception for teachers' technology integration that also extends to creating a supportive school environment by considering both internal and external factors.