The purpose of this quantitative study was to investigate the effect of prekindergarten attendance on boys' and girls' standardized reading achievement scores in third and fifth grade. The thrust for more emphasis on increased information regarding the impact that prekindergarten has on standardized test results, both short-term and long-term, is pertinent to educators. This study is critical in a time when meeting "adequate yearly progress" (AYP) has become increasingly more difficult for school districts, because proficiency level requirements continue to rise. In addition, the Commonwealth of Pennsylvania has proposed the new multiple measures evaluation system, which includes performance data from standardized test results from students as a factor into the teacher's performance evaluation. Existing research suggests that early learning experiences, like prekindergarten, positively impact a child's social, emotional and educational learning capacities. The long-term impact is relevant for parents and educators alike, in understanding the importance of learning opportunities from birth to age five. This understanding is relevant in helping to make informed decisions regarding prekindergarten enrollment. A causal comparative study was conducted to analyze standardized test results in reading achievement for 170 children residing in southeastern Pennsylvania. The results from this study will be helpful to various stakeholders keeping a watchful eye on early childhood education. Teachers, parents, administrators, school board members as well as political officials will develop a better understanding of how prekindergarten may affect children's long-range reading achievement. The research conducted identifies the level of attention that should be allocated for early learning initiatives and partnerships between districts and prekindergarten providers. Results from this study will aide school district personnel and early childhood advocates across the state to strategize recruitment initiatives regarding enrollment in prekindergarten. The research question associated with this study was: What is the effect of prekindergarten attendance on boys' and girls' standardized reading achievement test scores in third and fifth grade? [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.]