This quantitative quasi-experimental study examined the effect of brain-based instruction compared to teacher-centered instruction on student achievement in algebra I. A pre-test and post-test were given to a control group of 30 and experimental group of 42 before and after a unit if study in algebra I, which was taught using the two instructional methods. An independent t-test showed the equivalence of the two groups, while a paired t-test showed the achievement level of each group, an ANCOVA statistical analysis with the pre-test as the covariant showed the brain-based group had statistically significant higher achievement (p = 0.000) at the 95% confidence level. [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.]