The study's purpose was to determine the effectiveness of charter school programs in increasing academic achievement in students with disabilities who received special education services within one charter management organization. The study reviewed student achievement on a state standardized assessment in ELA and Mathematics. Relationships between race/ethnicity, socioeconomic status, gender, and achievement scores were also explored. Data consisted of means and standard deviations of the California Standardized Test scores for students receiving special education services in 2009-2010 and 2012-2013. Data were analyzed using a two-sample t-test. Results indicated students demonstrated better ELA and Math performance for the first two years of the study, ELA decreased in the last two. Factors of race/ethnicity, SES, and gender, showed female students performed better than males, White students typically performed better than Black and Hispanic, and students from non-disadvantaged backgrounds performed better than those from disadvantaged backgrounds. Conclusions drawn indicated students receiving special education services within one charter school system appeared to benefit. Findings appeared to taper off over the last two years of the study, indicating attendance within the same charter school system does not guarantee better performance. Future researchers may consider reviewing the range of "differentiated" services offered at charter schools such as interventions and accommodations, before or instead of special education. Lastly, future research should consider reviewing the supervision of charter schools' special education programs, staff professional development, and the educational level and viewpoints of staff members working in charter schools. [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.]