In-service professional development aims to change what experienced teachers do and think, using innovations to improve teaching and learning. Teachers' beliefs and classroom practice are linked, but how they interact is less certain, and how they are changed by professional development is presented in the research literature by various models: linear change from beliefs to classroom practice or vice versa, and cyclical or interactive models. The process of change in beliefs and classroom practice for a group of experienced in-service English teachers at universities in China was investigated during and after a professional development course. Qualitative case study methodology was used, with data collected from interviews and observations of teaching, and then analysed and interpreted inductively for emerging patterns. The findings suggest that the change process for experienced teachers is both more complex, more varied and less certain that presented in existing models. Multiple models of change in beliefs and classroom practice were present in the data, including linear change in different directions, and no change. In-service teacher educators are recommended to plan for this multiplicity of models of change in beliefs and classroom practice by taking into account each teacher's experience and existing teaching context.