The effectiveness of professional development programs for teachers in Turkey is limited because the programs are not designed to meet individual teacher needs. Although teachers are implementers who perform classroom practices, they are in the role of students in these programs. The project supported by The Scientific and Technological Research Institution of Turkey (TUBITAK) 1001-Grant 220K080 entitled "Designing and Evaluation of the Effectiveness of Scientific Inquiry Supported by Online Mentoring (e-scaffolding) in In-service Teacher Training" aims to examine and evaluate a professional development model. The project involves various strategies, such as mentorship, coaching, peer learning, and collaboration, for prioritizing teachers' ideas and expectations. This study intends to reveal the readiness of the stakeholders (participating teachers and mentors) in the online mentoring model supported by scientific inquiry as part of the professional development process of teachers. The prominent results of the research are that teachers have positive opinions about the importance of scientific inquiry-based learning and teaching, teachers' expectations from professional development programs vary by their levels of experience. In conclusion, this study is important in terms of making teachers' voices heard and designing professional development programs in line with their expectations.