This thesis examined the engagement of students at lower secondary schools in Finland. Two independent cross-sectional data sets collected in 2010 (N = 821) and 2013 (N = 2485) were analyzed using both variable-centered and personcentered methods. The thesis analyzed the associations between teacher– student relationships, family support for students’ learning, peer support at school, control and relevance of school work, students’ future aspirations and goals, school burnout, behavior at school, and truancy from school. The results offered three main findings. First, the structure of Finnish lower secondary school students’ affective and cognitive engagement, as assessed using the Finnish version of the Student Engagement Instrument (SEI-F), approximates the original theoretical structure. Second, three engagement and burnout profiles among the students were identified: high-engagement/low-burnout profile (40.6% of the sample), average-engagement/average-burnout profile (53.9%), and low-engagement/high-burnout profile (5.5%). Third, students’ perceptions of whether they receive support from teachers at their school – that is, affective engagement within the teacher–student relationships – were the most consistent correlate of their behavioral and cognitive engagement. Moreover, high support from family, good academic achievement and selfesteem, lack of truancy, female gender, studying at seventh grade as compared to eighth and ninth grades, living with at least one parent, and aiming to continue studying in high school after comprehensive school were other positive and significant correlates of engagement. Overall, the findings of this thesis suggest that the engagement of Finnish lower secondary students can be reliably captured using the SEI-F. The study adds to the understanding of students’ achievement and behavior at school and of the factors that associate positively with engagement. The results suggest that variation in students’ engagement is associated with at least partly malleable factors, such as academic achievement, which makes fostering of student engagement an important target for school interventions. As a practical implication of the findings, a three-tiered model of promoting student engagement is presented.