This quasi-experimental study aimed to examine the efficacy of the Sekolah Ramah Inklusi (SERASI) training program in improving the attitudes of teachers towards to inclusive education. The SERASI training program was developed for primary teachers in inclusive schools (n=19). This intervention comprised an 8 hours face-to-face training session encompassing three topics: disability, inclusive education, and teaching strategies. In order to determine the effects of the SERASI training program, the attitudes of teachers were measured using Kurniawati's (2016) adaptation of Mahat's (2008) Multidimensional Attitudes Toward Inclusive Education Scale (MATIES) and through observation and interviews with open-ended questions. All measurement tools were administered twice: before the training program was conducted and immediately afterwards. The outcomes obtained from the MATIES revealed no significant differences in the attitudes of teachers with regard to inclusive education although the mean scores of the pre-test (M=4.58) and the post-test (M=4.73) of the MATIES were different. In addition, the teachers felt that the SERASI training program accorded them the opportunity to better understand inclusive education and the strategies that they could apply in their classes, and that the training made them feel more confident of teaching an inclusive class. The results of the investigation thus demonstrated that the SERASI training program influences teachers in a positive manner. However, the SERASI training program was not found to be significantly effective in improving the attitudes of the teachers. These findings suggest that teachers in inclusive schools should receive a long-term training program and that they must be observed and interviewed to clearly comprehend the prevailing attitudes. Also, future researchers or schools should consider external factors such as the number of students with special education needs (SEN) or the facilities offered by the school to support inclusive education.