The main purpose of this study is to develop positive attitudes in high school teachers towards scientific research and project competitions by training them in scientific research and project preparation subjects. The study group consists of 90 high school teachers. As a result of the study, a significant difference was found in favor of post-test scores of high school teachers about their attitudes towards both scientific research and project competitions (p < .05). Furthermore, the attitudes of teachers towards project competitions, evaluation of projects included in the project competitions, being a mentor in these competitions and behaviors of students, which were considered to be positively changed by project competitions, were determined to be developed in a positive way. In addition, high school teachers developed a more positive attitude towards researchers and scientific research and it was concluded that there was no difference between attitudes of teachers towards scientific research in terms of their gender and educational level. Prior to the study, there was a weak, positive and statistically insignificant correlation between attitudes of high school teachers towards project competitions and scientific research (r = 0.149; p > .05). On the other hand, a moderate, positive and significant correlation was determined between attitudes of high school teachers towards project competitions and scientific research as a result of the study (r = 0.319; p < .05).