The objectives of this research were 1) to study the components affecting the administration of student care and assistance system based on Buddhadhamma in secondary schools under the Office of Bangkok Secondary Education Service Area, 2) to develop the effectiveness model of administration of student care and assistance system based on Buddhadhamma in secondary schools under the Office of Bangkok Secondary Education Service Area, and 3) to propose the effectiveness model for the administration of student care and assistance system based on Buddhadhamma in secondary schools under the Office of Bangkok Secondary Education Service Area. A multiphase mixed methods research was used to combine with quantitative research to expand the qualitative research results, divided into 3 phases: Phase 1-2 using qualitative research, key informants were 4 educational scholars, 10 key informants of monks, school administrators and teachers participating in the project, and the 9 experts of target group in focus group discussion and were selected by purposive sampling. Data was analyzed by using analytic induction. Phase 3 used quantitative research, a sample of 550 people was obtained by two-stage random sampling. Data were analyzed by descriptive statistics and research hypothesis was tested by checking the validity of the structural equation model using the LISREL program. Results were shown as follows: 1. Components of the effectiveness model for the administration of student care and assistance system based on Buddhadhamma in secondary schools under the Office of Bangkok Secondary Education Service Area consisted of 5 components: 1) school administration, 2) student care and assistance system process, 3) parent participation the roles of those involved in the student care and support assistance system; 4) Brahmavihāra IV, and 5) the effectiveness of the student care and assistance system. 2. The effectiveness model for the administration of student care and assistance system based on Buddhadhamma in secondary schools under the Office of Bangkok Secondary Education Service Area consisted of 3 exogenous latent variables: 1) school administration, there were 4 observed variables, namely 1) academic administration, 2) budget management, 3) personnel administration, and 4) General administration. 2) The process of the student assistance system 5 observed variables namely 1) knowing each student as an individual, 2) screening, 3) promotion and development, 4) prevention, assistance and correction, and 5) referral, and 3) roles of those involved in the student assistance system. There were 5 observed variables namely 1) management of school administrators, 2) performance of duties of advisors/class teachers, 3) students' cooperation, 4) student cooperation, support and consultation of the basic education committee, and 5) support for cooperation of parents/parent networks. There were 2 endogenous latent variables, namely 1) Brahmavihāra IV, that can be observed within 4 variables, namely 1) Metta, 2) Karuna, 3) Mudita, and 4) Upekkha. 2) The effectiveness of the student assistance system, 5 observed variables were 1) quality of learners, 2) awareness and appreciation of teachers, 3) drive of administrators' work systems, 4) parents' involvement with schools, and 5) performance of school. 3. The effectiveness model for the administration of student care and assistance system based on Buddhadhamma in secondary schools under the Office of Bangkok Secondary Education Service Area was consistent with empirical data (Chi-square = 215.76, df= 187, p= .07339, GFI=.976, AGFI=.946, RMR=.017), able to explain the variance in the effectiveness of student care and assistance system with 9.10 percent. It showed that the administration of educational institutions process of the student assistance system, parent involvement, the role of stakeholders in the student assistance system, and Brahmavihāra IV can promote the effectiveness of the student assistance system, and Brahmavihāra IV was the mediator in the effectiveness model for the administration of student care and assistance system based on Buddhadhamma in secondary schools under the Office of Bangkok Secondary Education Service Area.