The federal No Child Left Behind Act and previous performance-based accountability policies are based on a theoretical assumption that sanctions will motivate school staff to perform at higher levels and focus attention on student outcomes. Using data from Chicago, this article draws on expectancy and incentive theories to examine whether motivation levels changed as a result of accountability policies and the policy mechanisms that affected teacher motivation. Through a combination of qualitative and quantitative data, the authors found that the value teachers placed on their professional status and their goals for students focused and increased their effort, but low morale had the potential to undercut the sustainability of teachers' responses. (Contains 3 figures and 5 notes.)