This study examined the impact of high school students' graphing calculator usage on their math achievement over time. Achievement growth was measured using nationally-recognized standardized test scores from EXPLORE, PLAN, and ACT. Two groups of students were used in this study; one group had graphing calculators integrated beginning in freshman-year Algebra 1 and one group had graphing calculators integrated beginning in Algebra 2. Using standardized test scores from these two groups of students, a repeated-measures ANOVA test was performed. Data analysis produced a statistically significant model (z = 19.78, p < 0.0001). Two-sample t -tests were calculated and growth curves were plotted to look for further relationships. Although students who had graphing calculators integrated beginning in Algebra 2 scored higher on baseline EXPLORE tests, they experienced less growth over time than students who had graphing calculators integrated beginning in freshman-year Algebra 1. Male, female, Caucasian, and African-American students who had graphing calculators integrated into freshman-year Algebra 1 experienced more growth in achievement although the findings were not statistically significant. Implications for policy and practice focused on integrating graphing calculators throughout the mathematics curriculum beginning freshman year. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]