Today, many school districts are mandating tests to measure student performance and to hold individual schools and school systems accountable for that performance in order to meet the standards set forth in the No Child Left Behind Act (2001) and the Individuals with Disabilities Education Improvement Act (2004). The focus of this study was to examine the relationship among cognitive ability as measured by the Cognitive Abilities Test (CogAT) and measures of achievement, specifically, standardized achievement scores on the New Jersey Assessment of Skills and Knowledge (NJ ASK) and school grades. The current study investigated archival data of 452 seventh grade students enrolled in a large, suburban public school district during the 2007-2008 school year. Scores on the CogAT and NJ ASK were collected from grades 3, 5, and 7. Final grades in the subject areas of Reading, Writing, Math, Social Studies and Science were collected from report cards from the end of seventh grade of the 2007-2008 school year. Pearson correlations found significant relationships between: (1) cognitive ability and standardized achievement scores in grades 3, 5, and 7, (2) third grade cognitive ability and grade seven grades, and (3) third grade standardized achievement scores and grade seven grades. Further, out of the five cluster scores on the grade 3 CogAT and NJ ASK, the NJ ASK Language Arts score was the best predictor of grades in Reading and Writing and the NJ ASK Mathematics score was the best predictor of grades in Math, Science, and Social Studies. Finally, third grade NJ ASK Language Arts, NJ ASK Mathematics and CogAT Verbal scores were the best predictors of special education classification in grade 7, accounting for a combined 22% of the variance. Limitations to the study and implications for future research and practice are discussed. / School Psychology