By the end of the kindergarten, students are expected to possess early academic skills as well as the social maturity to be successful in first grade. Students leaving kindergarten without these readiness skills are sometimes held back in first grade or referred for a special education evaluation in later grades if they fail to make adequate progress. However, before a special education referral can be made, the education system must demonstrate that the deficit is not due to a lack of instruction. Response-to-Intervention is a preventive intervention framework supported by federal legislation (No Child Left Behind (NCLB); 2002 and Individuals with Disabilities Education Act (IDEIA); 2004) that ensures that only valid special education referrals (i.e., referrals based on quantitative data) are processed. Using a multi-tiered assessment and intervention approach, students are first identified as at-risk through the use of screening tools designed to indicate academic or behavioral deficits. At-risk students are then exposed to evidence-based interventions with increasing levels of intensity to determine the type and amount of support needed. However, response-to-intervention has yet to be extended down to kindergarten students, and the screening instruments available for this population have yet to be evaluated for their predictive validity with end of first grade academic and behavioral performance. This study examines the predictive validity of psychometrically sound academic and behavioral screening instruments with first grade academic and social-emotional success. Participants included kindergarten students (n = 290) from five ethnically diverse elementary schools located in a small suburban city in a mid-Atlantic state. Early literacy, early numeracy, writing, and social-emotional screening assessments were administered three times a year to determine whether the screening tools were adequate measures of kindergarten readiness skills for first grade academic and social-emotional success. Participants were followed from the beginning of kindergarten until the end of first grade to determine which skills measured by the screening assessments were the most predictive of a conceptual model of first grade academic and social-emotional success. The results indicated that the social-emotional screening assessment was able to significantly predict social-emotional success at the end of first grade. Kindergarten academic screening assessments however, were not able to significantly predict first grade academic success. Results also indicated that there were significant differences in scores across gender, ethnicity and family composition. [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.]