Professional wellbeing is a vital yet often neglected aspect of foreign language teaching. This book explores how teachers exercise their agency to sustain and enhance their wellbeing in the face of the unique demands of their profession. Drawing attention to the complex interplay between individual actions and contextual factors, it reveals how teachers build resilience, foster growth, and navigate challenges through their agentic choices. Central themes such as classroom instruction and management, professional development, emotional regulation, relationships, and coping with working conditions are presented as key dimensions of professional wellbeing. By highlighting these interconnected areas, the book offers valuable insights into the ways teachers shape their own professional paths. It provides researchers, educators, and policymakers with a deeper understanding of how agency for wellbeing can transform teaching practice and ensure that supporting teachers remains at the core of effective education.