The purpose of this quantitative correlational study is to determine if, and to what extent, there is a statistically significant relationship between the learning style of online postsecondary adult learners and their academic success as measured by their cumulative GPA. The theoretical basis for the study was Honey and Mumford's learning style theory and Kolb's experiential learning theory. The overarching research question sought to determine the relationship between variables learning style and academic success as measured by GPA. The study was conducted with a convenience sample of N = 135 teachers from a public school district in Missouri who have taken online graduate coursework. The results of Spearman's rho analysis found that the variable learning style did not have a statistically significant relationship with the variable academic success as measured by GPA of online postsecondary adult learners. Recommendations for future researchers to use a qualitative methodology to explore adult learners' perception of learning styles. Instead of self-reporting the data, future researchers may consider addressing the methodological limitations of the study using a more unbiased data collection method. Also, future researchers may consider offline data collection methods to ensure the inclusion of those adult learners who also took traditional courses. Lastly, future researchers should conduct a study that attempts to find if and to what extent teacher level of education relate to postsecondary learners' academic success, as no significance was found when looking at the learning style. [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.]