The aim of this research was to design a blended in-service training program for developing technopedagogical skills (B-INSET for TPD) in teaching English. 12 lecturers in an intensive English language program at a state university formed the study group in the research. In the design-based research, the expectations of the administrators, lecturers, and students about technology integration in the school where the research was conducted were identified. The program that was designed according to the principles of adult education, social constructivism, and blended learning was later improved based on the views of specialists from different fields, tested for ten weeks in the 2018-209 academic year fall semester, and evaluated by its participants. Questionnaire forms, semi-structured interviews, materials that were produced by the participants, face-to-face video sessions, and a research diary were utilized as data collection tools. The data were analyzed using descriptive statistics, descriptive analysis, and content analysis. At the end of the research, it was concluded that the participants found opportunities for interaction, collaboration, discussion, and hands-on practice when an eclectic teacher training model with the principles of adult education, social constructivism, and blended learning was utilized; and that the participants found adequate trainer support and all of their expectations were met.