Open AccessThe purpose of this study is to identify experienced teachers’ perceptions of and beliefs about their professional development; examine experienced teachers’ perceptions of their process of learning to teach and forming personal practical theories of teaching, and describe experienced teachers’ perceptions of significant experiences in their professional growth and personal development that shaped or influenced their approach to teaching. The experiences serve as a backdrop for understanding teachers’ beliefs about their professional growth. This qualitative study selected 10 experienced secondary teachers with more than 15 years of teaching experiences in Shin-Chu District in Taiwan. Data collection techniques include: (1) semi-structured individual interviews; (2) informal observations, interviews, and field notes, and (3) documents and records. The OSR-NUD*IST qualitative data analysis computer software program was used as the tool for data analysis. The following conclusions were based on the results of the analysis of the data: knowledge about teachers’ beliefs about professional development, and knowledge about practice that facilitated teachers’ personal development. The emerging concerns and beliefs identified in this study included: (a) beliefs about professional development; (b) beliefs about teachers’ learning; (c) beliefs about teachers’ role; and (d) teachers’ beliefs about curriculum.