The purposes of this research were; To apply of Theory-Driven Evaluation; To develop and to evaluate the student’s democratic personality development project in school under the Office of Basic Education Commission. The samples were 38 students studying in grade 4/1 in Sansai Luang school, Sansai district, Chiang Mai province. The stakeholders were Ministry of Education, Office of Election Commission, the school director, a social study teacher, the teacher of grade 4/1 class, and 38 parents. The research procedure was divided in 3 parts: Part 1: Creating the program theory for evaluation, the concept of application of Theory-Driven Evaluation to develop and evaluate the project was provided to the stakeholders in focus group. Including, the researcher knew the causes of the students’ personality, behavior or desired characteristics problems, the needs, and the method of the students’ learning. This was for setting of the context of activity, the process of teaching-learning, and the evaluation of the project from the beginning to at the end of the project. Part 2: The developing of the method of evaluation, after getting the intervention (22 activities), the form of evaluations were created as 1) the exam papers of 22 activities, the evaluation of the students’ satisfaction on the activities teaching-learning, and students’ behavior record of the classroom teacher and students from the beginning to the end of the project and 2) six forms of the project evaluation. Part 3: evaluating the project, the developed forms of evaluation as mentioned above were used to evaluate the success of the project after 1 semester by asking the stakeholders and the students. The results of the study were as follows: 1. The program theory was created, consisting of action model and change model. The action model used to design intervention (22 activities), which consisted of three principles of Buddhism: casa ruatrarom/carmi's fair, harmony and intelligence fair. Each activity composed of context, the process of teaching-learning conformed to students’ learning and evaluating in before, between and at the end of project, and planning of interventions used to practice. And the change model consisted of interventions, determinant and outcome. The developed program linked intervention and students’ demographic behavior where awareness, consciousness was a determinant or mediate variable. 2. The overall of the students’ score and their satisfaction on the learning-teaching process of 22 activities were at a good level. The overall of students’ satisfaction in both good members and good citizen were at a very satisfied level. The overall of most students’ democratic personality/behavior at the end of the project was at a very high level. The students’ awareness/consciousness instilling democratic behaviors was moderately. The overall students’ satisfaction was at an extremely high level. The thoughts learned from what they derived in all activities of democratic personality/behaviors development were ethics, benefaction, responsibility, acceptance of individual differences, and harmony with one another. They will be able to bring the knowledge learned to good use in their daily lives. The stakeholders agreed with this project since this project instilled good benefits to their children in their daily lives. The overall of the students’ democratic personality/behaviors was at a high level.