Despite the availability of and pressures to incorporate educational technology into secondary curriculum, schools have not shown that technology is being adequately used by educators or that students in fact know how to use them. In particular, many teachers are not using technology such as graphing calculators as an instructional mathematics resource. The purpose of this quantitative, quasi-experimental study was to determine the effects of graphing calculator use on students' mathematical performance. To achieve this purpose, the study compared the performance of students who used a graphing calculator to complete a standardized Algebra II assessment to the performance of students who did not use a graphing calculator to complete the same assessment. Descriptive statistics were used to provide information about the grouped scores for each item, number of students who completed each item, the spread of responses across each group, the range of scores, and the mean score of each question for the control group and for the treatment group. T-tests were completed and provided comparisons of data from both the control group and treatment group responses. The results of the t- tests for independent means compared the measures of student performance with whether the student used a graphing calculator or not. Results of the t-tests found the student's total score to be significantly higher for students who used the graphing calculator ( M = 0.54) when compared to those students who did not use the graphing calculator (M = 0.42), t (51) = 2.69, p = 0.01. [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.]