The purpose of this study was to measure the association between school-wide student achievement on the English and mathematics Standards of Learning (SOL) tests and the degree of implementation and length of time implementing Response to Intervention (RTI) in Virginia middle schools. Recognizing that RTI is a complex process (Fuchs and Deshler, 2007; Mellard, Frey, and Woods, 2012; Mellard, McKnight, and Jordan, 2010; VanDerHeyden, Witt, and Barnett, 2005), some middle schools may experience uneven degrees of implementation in their attempts to adopt the RTI model (Mellard, Frey, and Woods, 2012). Principals serving grades 6 through 8 exclusively in Virginia were surveyed using an adapted version of the Self Assessment of Problem Solving Implementation (Castillo, J., Batsche, G., Curtis, M., Stockslage, K., March, A., and Minch, D., 2010), a Likert-like scale, to determine the degree of RTI implementation and the length of time the school had been implementing RTI. The school's implementation score and the number of years the schools had been implementing RTI were regressed against the school's school-wide scaled scores on the Standards of Learning (SOL) tests in English and mathematics. Analysis of the association between Response to Intervention implementation levels and the number of years a school had implemented Response to Intervention failed to reveal significant findings on student achievement in reading. RTI implementation levels showed a significant negative association with mathematics SOL scaled scores in the participating middle schools.