Educational reform efforts support professional development (PD) programs for teachers as a means to establishing possible outcomes that may affect changing teacher practices, student learning, and impact on economic and educational foundations. PD programs require evaluation in order to appraise their effectiveness, and seeking participant opinion following program implementation is one such valid method. The aim of the current study is to determine in-service physics teachers' evaluation about the impact of a long-term PD program. Qualitative research methodology was employed in this study. Research was conducted with seven teachers, with data collected through a workshop session evaluation checklist (WSEC) and a PD program evaluation interview protocol (PDEIP). Interviews were audio-recorded and then responses to each question transcribed. According to the WSEC data, all sessions broadly reached their aims. The session which teachers considered the least contributive to their developmental gain was on the topic of "Misconception." The PDEIP results showed that teachers used more student-centered methods and more varied teaching materials in their lessons following their participation in the PD program. Following the PD program, some teachers reportedly started using placement assessment.