Research on the role of teacher agency has been growing significantly during the last decade. Agentic teachers act purposefully and constructively to direct their professional development and contribute to the quality of education, especially in rural areas. Professional development is mutually constituted between teachers and socio-cultural conditions (e.g., circumstances, physical artifacts, power relations, and school cultures) that constrain or enable their agency. This study explored teacher professional agency, and its relationship to teacher perceived social structure, using two newly developed scales: (1) the Teacher Professional Agency (TPA) and (2) the Teacher-Perceived Social Structure (TPSS). A total number of 592 teachers working at rural schools in western China completed the questionnaire. The findings revealed that the two scales were valid and reliable instruments for measuring teacher professional agency, and teacher perceived social structure. Findings show a modestly-moderately correlation between teachers' professional identity and their perceived social identity. Collegial relationships, followed by school climate and social identity, have the strongest impact on teachers' professional agency.