This quantitative causal comparative study looked to see if there was a relationship between childhood obesity and student achievement. Because of the many conflicting results in the research available, it was not known if there was a relationship between childhood obesity and student achievement among inner-city middle school students in a school in Trenton, New Jersey. This research looked to see if there was a statistical significance between obese sixth, seventh, and eighth grade students' standardized test scores versus non-obese sixth, seventh, and eighth grade students' standardized test scores. Data were collected in the form of heights and weights of 224 middle school students in Trenton, New Jersey to configure their BMI percentile as well as standardized test scores of those students during the 2011-2012 school year. This study was based on Albert Bandura's social learning cognitive theory. Pearson product moment analyses were conducted to see if there was a relationship between BMI and standardized test scores. T-tests were also conducted to see if there was a statistical significance between obese students and non-obese students in their tests scores. The results indicated that there was no correlation between BMI and standardized test scores. Further results indicated that there was no statistically significant difference between obese students and non-obese students in their test scores with one exception. Statistically, seventh grade obese students scored lower on the math section of the standardized test than non-obese seventh grade students. Future research needs to be completed using middle school students but with a larger population sample size with more students from multiple middle schools. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]