This mixed methods research uses econometric analysis and thematic analysis to identify the practices of teachers, in a selected sample of disadvantaged schools in Mexico with high value-added scores and engaging lessons. In the first chapter, a review of the literature is conducted to explore the definition of student engagement, determine the factors that facilitate it, and examine its relevance for achievement. As a result of the review, student engagement was defined in the research as a metaconstruct with cognitive, behavioural and emotional components. The review revealed that student engagement is influenced by home and personal factors, school factors, and classroom factors. Among the latter, the literature provides evidence that teachers’ practices play a major role in promoting student engagement, and teachers act as mediators between student engagement and achievement. The second chapter examines the design and methodology of the research. The final four chapters investigate whether the schools in the sample fit the theoretical proposition of the research, that there are marginal primary schools in Mexico, where students outperform their peers on the national standardized test, due to the teachers’ ability to engage students; and investigate what those practices in the selected schools are. Results from a random effects model, which used data from 315 6th-grade students in 18 schools, revealed a positive and significant correlation between student engagement and teacher practices, clarity, academic press, academic personalism, trust, and rigour; and the variables parental support and teacher qualification. Results from a multiple case study conducted in two of the 18 schools, and where students reported relative high levels of student engagement, corroborated the importance of the practices, academic personalism, trust, academic press, and parental involvement. In addition, school leadership, discipline, and the students’ exposure to fun and creative lessons delivered by an enthusiastic teacher, were also found to be promoters of student engagement. The difficult socioeconomic background of the students and lack of incentives for the teachers, were found to be challenges to student engagement.