In this study, Seminars were envisaged on the importance of stem education at secondary schools. Basicly these seminars were about to introduce STEM education to the teachers. Pre-test and post-tests were applied in the study. By this way, it was aimed to measure the effectiveness of the seminars on especially maths and technology related courses of teachers. Three scales are used to test the effectiveness of the seminars. As for the results it was found that teachers were positively effected by the mathematical self literacy but had no difference in their mathematical thinking ability and in terms of their technological use.