Purpose: The Santa Ana Unified School District received an i3 grant (Investing in Innovation; funded by the U.S. Department of Education Grant number U411C160074) to build on their existing school climate practices. Called the Enhanced Positive School Climate Model, the aim is to improve school climate, student-adult relationships, create social emotional learning programs, and provide students the needed structure to access challenging curriculum and expectations. As part of this enhanced model, School Climate Liaisons (SCLs) were hired to support and provide coaching to schools in the intervention group on PBIS [Positive Behavioral Intervention and Supports], RP [Restorative Practice] implementation, and behavioral interventions. As part of the i3 grant requirements, the district employed a rigorous cluster-randomized trial whereby half of the district's elementary schools were assigned to receive the Enhanced Positive School Climate Model and half were assigned to a waitlist control. The confirmatory research question is: Do students in grades 4 and 5 at follow-up, in schools assigned to receive support from PBIS and Restorative Practice school climate specialists and community liaisons, who receive services for two years, exhibit higher levels of self-management at the end of the second year, as compared to students in grades 4 and 5 in schools assigned to not receive such support? Additionally, there were exploratory research questions examining changes in other SEL [social-emotional learning] measures including growth mindset, self-efficacy, and social awareness. Methods: This study employed a cluster-randomized controlled design whereby half of the study schools were assigned to the treatment condition and the other half of schools were assigned to the "business as usual" control condition. In total, 35 schools (30 K-5 schools; 5 K-8 schools) were randomly assigned to either the treatment or control condition. All students within these schools were included in the evaluation. Students in the treatment schools (n = 17) were eligible to receive services through the grant. Randomization occurred in May 2017. The 2016-17 school year served as a baseline school year (i.e., no services were provided). The Enhanced Positive School Climate Model began in the 2017-18 school year and continued into the 2018-19 school year for treatment schools only. Control schools were waitlisted and began receiving services in the 2019-20 school year. Students enrolled in district schools in May 2017 were tracked using student roster information through the end of the 2018-19 school year. Only students who were in study schools continuously from the 2016-2017 to 2018-2019 school years were included in the impact analysis. The confirmatory and exploratory outcomes referenced below were conducted using extant data from the district. Data were used from routine data collection processes within the district from the annual CORE climate student survey. The primary outcome measure was the five-item self-management scale on the CORE District's student survey (Taylor, Oberle, Durlak, & Weissberg, 2017; Transforming Education, 2014; https://www.rand.org/education-and-labor/projects/assessments/tool/2014/panorama-social-emotional-learning-questionnaire-measures.html) asked of all students in grades 4-12 each year. For the confirmatory research question (and all exploratory questions), adjusted post-intervention outcomes for students in treatment schools were compared to the outcomes for their counterparts in the control schools. This involved fitting conditional multilevel regression models (i.e., hierarchical linear modeling [HLM]), with additional terms to account for the nesting of individuals within schools (see Goldstein 1987; Raudenbush & Bryk, 2002; Murray 1998). Results: Eight two-level models were estimated per grade level to address the confirmatory and exploratory research questions. Although the students in treatment schools had slightly higher self-management, growth mindset and self-efficacy scores at follow-up, only the difference in fourth grade self-efficacy scores was statistically significant. In contrast, students in control schools had very slightly higher social awareness scores; this finding was not statistically significant. Implications: Meaningful and statistically significant differences were not found between students who attended schools that received the Enhanced Positive School Climate Model compared to their peers in schools that did not receive the Enhanced Positive School Climate Model. The lack of findings may be due to the other changes in school climate practices throughout the district during the study period. Additionally, variations in the implementation of the Enhanced Positive School Climate Model may have contributed to the lack of findings. Although the findings are not significant, the direction of results is mostly consistent, indicating increases in SEL competencies for students receiving additional school climate supports. Future studies should continue to investigate the relationship between whole-school approaches to school climate and changes in SEL competencies for students.