In this study, examining the effectiveness of in-service training for gifted education has been conducted. In the study, 30 Classroom, Science, Mathematics and Preschool teachers working at schools in different cities of Turkey, took part as volunteer participants. Moreover, some criteria were specified for determining the participants. In this in-service training, teachers have received theoretical and practical training in the academicians who study on gifted education. In this process, they have designed units in groups according to the Education Program for Gifted Student Bridge with University (EPGBU) curriculum. The research has been designed as a case-study research which is one of the qualitative research models. In the study, some data tools (scales, interview form and the documents) were utilized Two of data collection tools were developed by research. These were Science Fair Mentorship Self-efficacy Scale for Teachers (SFMSST) and Gifted Education Self-efficacy Scale for Teachers (GESST). As a result of a one-week in-service training, it has been determined that the teachers' perception of self-efficacy for scientific research mentorship and gifted education increased. [This study was financially supported by STRCT (TÜBITAK).]