The purpose of this causal comparative study was to determine the impact of the implementation of NCLB on the performance levels of gifted students relative to those of non-gifted students. The study involved the 2001, 2002, 2008, and 2009 Georgia Criterion-Referenced Competency Tests (CRCT) results of 1,978 middle grades students from a school in rural Northwest Georgia. The analysis included comparing the Mann-Whitney statistics, two-sample independent z-test statistics, and the percentage of improvement in performance levels of the gifted and non-gifted students, as measured by the CRCT in reading, language arts, and mathematics. The findings revealed that, since the implementation of NCLB, both the gifted and non-gifted students experienced a statistically significant increase in their performance levels on the CRCT. However, the difference between the percentages of improvement in the performance levels of the gifted students relative to those of the non-gifted students was statistically non-significant.