Since science education is a field that is open to current developments due to its nature, science educators need to be in a professional development process that frequently updates themselves. In this study, a metasynthesis of studies focusing on in-service professional development for science teachers was made. Content analysis, one of the qualitative research methods, was used in the examination of 37 articles that met the criteria. It had been observed that descriptive studies the current situations are mostly on "general evaluation of in-service professional development programs". It has been found that negative thoughts are at the forefront in the results of research findings in this aim. It has been determined that the most frequently studied themes involving experimental procedure researches on professional development practices for teachers are "in-service training practice and evaluation" and "collaborative practices" and positive results have been obtained from these studies. The theme of "collaboration" for science teachers' professional development has come to the fore in both descriptive and involving experimental procedure research. In the light of the results of the research, suggestions were made with the idea that there should be more studies that examine "the teacher as a part of a social structure" rather than "individual professional development" prepared by considering the teacher as an individual separate from the student and the school.