This paper reports on a study of the relationship between teacher evaluation scores in a school implementing knowledge- and skills-based pay and classroom student achievement. The study occurred in a California charter elementary school that was 100 percent Title I, 100 percent free/reduced lunch, and had predominantly limited English speaking students. The school had historically low achievement, and for 4 years, it had been implementing a performance evaluation and pay plan under which teachers were evaluated, rated, and paid accordingly. For the study, data were collected on 34 teachers and all of their students for whom 2 years of achievement data were available. Researchers estimated classroom effects, analyzed their relationship to teacher evaluation scores, and examined teacher evaluation scores as level 2 explanatory variables in hierarchical linear models of student achievement. Results indicated that there was a clear difference in the strength of the relationship between teacher evaluation scores and classroom achievement in reading compared with mathematics or language arts. An appendix presents descriptive statistics. (Contains 37 bibliographic references.) (SM)