The purpose of this study was to determine if the four assessments for entrance into an academic middle school gifted English program were accurately predicting success, as measured by students’ grades each nine-week grading period. Some students were dismissed from the program each year because they could not maintain the required minimum average of 80%. The four entrance assessments evaluated were the Cognitive Abilities Test (CogAT), Naglieri Nonverbal Ability Test (NNAT), STEP Writing test, and the Iowa Test of Basic Skills: Reading (ITBS). The sample consisted of 150 sixth, seventh, and eighth grade students studied longitudinally over the span of four years from a suburban middle school in a large Texas school district. Using correlation, logistic regression, and generalized linear regression models, the results showed that all the students selected to participate in the middle school gifted English program were statistically capable of success, whether they successfully remained in the program or not. Additionally, the results indicated that the two achievement tests (ITBS Reading and STEP Writing test) better predicted which students were successful, whereas the aptitude tests (CogAT and NNAT) did not. The achievement tests were determined to be better predictors of students’ success, as measured by grades, in this rigorous academic middle school gifted English program. Other findings include (a) students’ grades increased over time in the program, (b) females were predicted to earn about two point higher grades than males, and (c) the individual student was a significant predictor of success based on entrance scores. Finally, several recommendations were made for future research. These possibilities include repeating this study using standard scores for data analysis rather than the percentile scores that were available for this investigation. An additional recommendation is to investigate a possible replacement for the STEP Writing test, as it has not been nationally normed in decades. Another possibility would be to evaluate the curriculum and teacher effectiveness within the district using the NAGC (2010b) Pre-K-Grade 12 Gifted Programming Standards. A final potential study could implement specific interventions for use with students at-risk for underachievement to determine which strategies are most effective.