The objectives of this research are 1) to study the students’ opinion of Buddhist monks’ role to the moral development in secondary schools, 2) to compare the students’ opinion of monks’ role paid to the moral development in secondary education school in Nkhonchaisi District, nakhonpathom Province, by separating in individual and 3) to study the problems, obstacles and proposals of monks’ role to the moral development in secondary education schools in Nakhonchaisi District, nakhonpathom Province. The method used in the process of the research was the mixed method research, that was, the quantitative research used for collecting the data in the form of using the questionnaire and the qualitative research used for collecting the data in the form of in-depth interview. The populations were the 932 students studying in the upper secondary education classes of Phloychatruchinda school, Ubonratanaratchakanya Rajvidyalaya Nakhonpathom, Phoempanya school, Laembuavidya school, Phatrayanawitthaya school and Ngiuruai bunmirangsarit school, belonging to the Office of Secondary Education Zone, Zone 9. The instruments used for collecting the data consist of the forms for interview, the form for field record and the questionnaire of the opinion. The packaged program was used for analyzing the data from the questionnaire, with statistical percentage for general data of answer givers to questionnaire. The statistics was used for valuating mean and standard deviation of the opinion level. The content analysis was used for data from the field record.

              From the result of the research, it has been found that

              1. The students’ opinion on monks’ role paid to the moral development in secondary education schools in Nakhonchaisi District, Nakhonpathom Province, in generally, was at the level “ much “ X =4.07. For considering as aspects, it has been found that in the aspect of teaching, it was at the higher level X = 4.09 and in the aspect of teaching and training in the morality was at the lowest level X = 4.05

              2.The comparative result of monks’ role to the moral development in the secondary education school, in Nakhonchaisi District, Nakhonpathom Province, being separated by sex, age, education and grade of learning, it has been found that the students’ opinion of monks’ role to the moral development in the secondary education schools in Nakhonchaisi District, Nakhonpathom Province, in the aspect of teaching and training in morality, supporting the moral activities, giving the moral advice and the aspect of learning and teaching, the opinion of the questionnaire answer givers was at the level “much “ in every item. This was in the line with the fact. Hereby, all the items of  the research hypothesis set were refused.

              3 The proposals of monks’ role to the moral development in the secondary education schools in Nakhonchaisi District, Nakhonpathon Prvince have been found that 1) in the aspect of teaching and training I morality, monks should hold more training activities in schools and monks should used the easy media for understanding in order to attract the youths. 2) in the aspect of supporting the moral activities, the more supporting activities should be held. For example, activities on   Buddhist holy days and it should be help continuously . 3) in the aspect of giving the moral advices, monks should do more teaching the Buddhist doctrine and should give a chance to students to present their opinion of the essence of learning, 4) in the aspect of learning and teaching, the educational media should be used for supporting the learning essence, without emphasizing on the difficult content.