Teacher concerns influence how teachers respond to education reform. The 12-Year Basic Education is a curriculum reform focusing on a competency-based curriculum and instruction in Taiwan. The aim of the current study was to investigate the stages and types of gifted education teachers' concerns about competency-based instruction based on the Concerns-Based Adoption Model. A survey was administered to 274 gifted education teachers. The findings indicated that the gifted education teachers' concern profiles were very similar. Teacher concerns fell into three relatively well-defined stages: the Information concern (stage 1), Refocusing (stage 6), and Personal (stage 2). In addition, teacher concerns were clustered into three types: (1) pursuing change agency with dialectical thinking; (2) looking for efficiency by managing resources; and (3) awareness of current situations but working individually. Each type consisted of its own characteristics and the developmental stages of concern. Recommendations for practice and future studies are also provided.