The purpose of this program evaluation was to identify the effects of Small Learning Community (SLC) reforms on school climate, student attitudes and student performance. Eight SLC programs in five Albuquerque high schools were studied for one to four years, depending on each program's date of inception. Data were collected from students, teachers, administrators, and parents using surveys, focus groups, interviews, activity logs and the district's student information system. SLC groups were compared to non-SLC groups within the same schools, controlling for prior academic achievement and demographic variables. Results indicate that SLCs produced statistically significant improvements in school climate, student dropout, attendance and grade completion. SLC students were more likely than non-SLC students to feel visible, safe, engaged and held to high academic standards. They were more likely to earn enough credits to pass to the next grade level, more likely to attend classes, and less likely to drop out of school. Results also showed that faithful implementation of the research-based SLC model yielded the strongest results, and that teacher collaboration and team exclusivity were two keys to success. In conclusion, SLCs can have a significant impact on school climate, student attitudes and students' academic persistence. Schools and districts can maximize success by allocating sufficient time, funding, space, administrative support and other resources that ensure fidelity to the SLC program model. (Contains 1 table, 1 figure, and 5 footnotes.)