The objectives of this study were to: 1) construct a training course of spiritual leadership for those preparing to become administrators in Catholic schools in Thailand; 2) implement and utilize the training course, and 3) analyze, evaluate and enhance the training course. The sample used in this research was 32 young participants who were preparing themselves to be the administrators of Catholic schools in Thailand. The research steps were: 1) the requirement assessment, 2) training course development, 3) the training course experiment, and 4) training course optimization. This is a research and development project. The methodologies used in this study were the cognitive and attitude test, semi-structured interviews and the suitability evaluation form of the training course. The findings of this study can be summarized as follows: 1) The training course in spiritual leadership to prepare administrators of Catholic schools in Thailand consists of five modules: 1. Towards a theory of spiritual leadership, 2. Vision, 3. Altruistic love, 4. Faith and hope, and 5. Example of success; 2) the results of the experiment revealed that after completing the training course, the religious participants who had prepared themselves to be Catholic school administrators in Thailand got higher scores on cognitive and attitude tests, with total scores in the evaluation reaching 4.76 (the highest level); 3) the training course was improved by extending the training session from two days to three days, and conducting a bilingual PowerPoint presentation.