Abstract
This paper defines job performance as a social construct from different perspectives, such as standards, behaviour, and process. A comprehensive model was constructed to explain the multiple realities of the job performance of professional social workers. The different perspectives of job performance: organizational performance, staff performance and quality of service were discussed. The dynamic relationships between various factors behind these components were also identified. Supervision and professional development for social workers, goals setting and strategy formulation for human service organizations, and programme evaluation for service delivery were proposed as guidelines for improving job performance of professional social workers.