Successful social and emotional learning (SEL) programs have established methods with teacher and peer support that improve prosocial behavior. Research has shown intervention programs that incorporate these skills reduce antisocial behaviors, but implementation in schools may vary and therefore affect outcomes. The purpose of this non-experimental program evaluation study was to understand the perceptions of implementation, impact, acceptability, and effects of Second Step within a suburban elementary classroom in the northeastern United States. The participants were teachers in a suburban elementary school near a large northeastern US city. A questionnaire, observations, interviews, a focus group, and school collected data (e.g., Pennsylvania System of School Assessment (PSSA) testing) were used to answer the research questions. Participants reported perceptions that Second Step had positive effects on academic performance. PSSA data showed that student academic performance appeared to be minimally affected or unaffected by Second Step. Results from the questionnaire, interviews, and focus group suggest teachers believed Second Step improved student behavior. However, the school did not collect behavioral data (e.g., suspensions, referrals, detentions, etc.) prior to or after Second Step adoption. Limited training and other factors may explain why reported fidelity to the curriculum appeared inconsistent with observational measures. Participant bias may have also influenced interview and focus group data. Despite limitations, schools that adopt Second Step should rely on evaluations to determine whether intended impacts are realized. Also, Second Step and other SEL curriculum researchers should consider providing guidance about implementation, assessment, and cost-benefit analysis. Researchers could investigate systematic changes to lesson content and delivery in ways that allow teachers to adapt or modify instruction without compromising curricular effects. [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.]