It is the purpose of this study to examine the effects of the unionisation status of US school districts on teacher job satisfaction. Using an ordered probit analysis and a sample of public school teachers, results of the present study suggest that teachers working in unionised districts are, overall, less satisfied with their jobs than are teachers in non-unionised districts. However, teachers in unionised districts were less likely to leave for better pay and were more enthusiastic about teaching than teachers in non-unionised districts. Hence, even though teachers in unionised districts were generally less satisfied with their jobs, they were more satisfied with regards to certain specific aspects of their positions.