Abstract: This study examined the influence on student enrollment and pass rates of a variable pay for performance incentive program in Texas. The incentive was one component in a broader educational intervention by the Advanced Placement Strategies, Inc. The goal of the incentive program was to increase the total number of qualifying scores in AP courses, especially in math, science, and English. The study used two sources of data. The first was a survey of AP classroom teachers in sampled Texas public high schools. The second consisted of College Board frequency data for sampled schools in 1996, 2001, and 2006. Comparing two similar groups of schools in Texas, the study found the incentive program was associated with higher levels of student participation and qualifying scores per thousand enrolled juniors and seniors, but not higher pass rates overall. A sub analysis of the survey data revealed evidence of higher pass rates for incentivized when compared to non-incentivized AP teachers. AP teachers expressed mixed feelings about the effectiveness and fairness of incentives tied to student achievement, with incentivized teachers generally more favorably disposed to the principle of pay for performance than non-incentivized teachers.