Using statewide longitudinal teacher survey data collected in 2009 and 2010, this study examined the characteristics of teacher evaluation used to determine performance-related pay (PRP), and the association between PRP and improvement in the practice of constructivist instruction. The study found that 10.9% of middle school mathematics teachers in Missouri received PRP in 2009 and the average amount was US$1,463. The teachers were mainly evaluated by principals who conducted classroom observations and held face-to-face meetings to assess their teaching practice and professional development activities. After controlling for the background characteristics, this study found a modest yet positive association between PRP and improvement in teacher practice of constructivist instruction from 2009 to 2010.