The purpose of this study was to assess the effect of the Georgia Department of Education Science Specialist teacher-mentoring program on student achievement on science standardized tests. This study analyzed the impact this program has had on student achievement in participating high schools when compared with high schools across the state where the program had not intervened. The Georgia High School Graduation Test, physical science end-of-course, and biology end-of-course test data, from a three year period, were collected from the Georgia Department of Education website and analyzed using an independent-t test and the Mann-Whitney test. While test score improvements cannot be entirely attributed to the Science Specialist mentoring program, the study revealed state-wide increases in physical science end-of-course tests and the Georgia High School Graduation Test scores over the three-year period in those schools participating in the teacher-mentoring program. Significant increases in students with disabilities populations and economically disadvantaged populations were also noted. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]