The purpose of this research was to examine the impact of the Maryland School Performance Assessment Program (MSPAP) and the Maryland Learning Outcomes (MLOs) in a number of areas including teacher, principal, and student beliefs, classroom practices, and student learning in reading and writing. A statewide sample of 90 elementary and middle schools in Maryland participated in the study. Questionnaires were administered to principals, teachers, and students. Additionally, classroom instruction and assessment materials were collected from teachers, and student performance on MSPAP over 5 years was obtained. Results indicated that principals and teachers tended to be supportive of MSPAP, reading and writing classroom practices were somewhat aligned with the goals of MSPAP, and greater performance gains in reading and writing tended to occur in schools that reported increased use of reform-oriented instruction. The methodology and interpretive outcomes in the study contribute to the growing literature base on the effects of high stakes testing. (Contains 12 tables and 3 notes.)