Background: Education has much in common with professions that are using positive psychology and positive organizational scholarship to transform practice, yet the science behind peak human and group functioning has been slow to displace deficit-based framing of reform policies and improvement strategies in education. Purpose of the Study: This study used self-determination theory to identify a general type of instructional environment that has positive consequences for learning outcomes. We hypothesized that a self-regulatory climate is related to school-level differences in student reading growth and that student perceptions of autonomy-supportive instruction are related to student differences in reading growth. Setting: Data were collected during the 2013-2014 school year from a city school system, located in a metropolitan area of about 900,000 residents, that serves approximately 42,000 students in 88 school sites. During the 2013-2014 school year, 80% of the students qualified for free or reduced-priced lunch (FRL); 26% were Black, 27% White, 30% Hispanic, 6% Native American, 9% multiracial, and 1% Asian. For this study, data come from students and teachers at all 51 elementary schools in the school system that have a 5th grade. Data Analysis: Hypotheses were tested using a three-level linear growth analysis in HLM 7.0. The first step was to estimate the average reading growth for fifth-grade students using an unconditional growth model. The second step was to test a controlled-effects growth model, with FRL and racial/ethnic minority status included as student controls and FRL rate and percentage of White students enrolled in the school as school-level controls; self-regulatory climate was entered as a school-level predictor in this model. The final step was to add student-perceived autonomy-supportive instruction as a student-level explanatory variable. Findings: Results showed that students in schools with self-regulatory climates achieved a higher reading growth rate than other students. Similar results were found with autonomy-supportive instruction: Students who experienced classroom instruction as autonomy-supportive had higher average reading growth than other students. Conclusions: The aim of positive education is to develop a body of scientific evidence capable of explaining sources of exceptional teaching and learning. Self-regulatory climate and autonomy-supportive instruction appear to be two positive school conditions that enable students to flourish.