The problem addressed through this study was the potential effects of the lack of parent participation at individualized education plan (IEP) meetings on students' achievement. The research question in this study examined the relationship between parents of high school students with disabilities (SWD) attendance at annual IEP meetings and students' test scores on Northwest Evaluation Association Measures of Academic Progress (NWEA MAP) Growth reading and math benchmark test scores versus scores of parents who did not attend. The difference was examined between NWEA MAP Growth reading and math scores for 11th grade parents who attended the annual IEP meeting and those who did not attend. An ex post facto design was used to examine records of parents' attendance and non-attendance at IEP meetings along with benchmark test scores from the NWEA Map Growth reading and math scores. The theoretical framework was Hoover-Dempsey and Sandler's model of parental involvement. Independent samples t tests were used for the data analysis. Although there was a slight increase in the benchmark scores of the SWD whose parent attended the annual IEP, the difference was not significant based on the results. The results suggest that parent attendance at IEP meetings was not a significant factor in stronger achievement test scores for SWD. This study may positively affect social change by supporting the examination of other factors that might affect benchmark achievement test scores among SWD. [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.]