The purpose of this study was to examine the effects of the Mathematics Quality Core Curriculum (QCC) and the Mathematics Georgia Performance Standards (GPS) on high school student achievement as measured by the SAT and ACT. The State of Georgia redesigned the mathematics curriculum in order to show higher achievement in mathematics by increasing the rigor. One would assume overall SAT and ACT math scores should increase. The National Council of Teachers of Mathematics (NCTM) (2013) stated improvement will take commitment and patience that may not come for a number of years. This study explored the effectiveness of mathematics curriculum reform. The findings of the study have the potential to inform future revisions of the Mathematics Georgia Standards of Excellence (MGSE) or other Georgia Curricula. The study used an ex post facto design with quantitative methods. Quantitative data were calculated for each research question to determine significant differences between the QCC and GPS curriculum models. SAT and ACT mean scores were evaluated using a series of paired t tests providing a comparison between each model. Descriptive statistics were assessed to look at increases and decreases in the mean scores to identify minor and major differences. Overall, it was found that the changes in curriculum made no difference in the mathematics achievement of students in Georgia. However, a comparison of schools in Georgia suggested small schools experienced small increases in mathematics achievement while large Title I schools experienced slight decreases in mathematics achievement.