Echoing research interests in recent concepts and models of teacher leadership, the focus of existing scales needs to be updated, and their quality needs to be improved. This study summarizes common ground of influential definitions, models, and frameworks for teacher leadership, proposes a six-factor model (association, professional learning, assessment, instruction, community, and policy leadership), and develops the corresponding scale. The data from 534 teachers (97% from public schools) support the model, confirm psychometric quality of the scale, and reveal characteristics of teacher leadership in four cities in China. The scale is used in future studies as a measurement instrument and in practice to assess teacher leadership development.