This research project aims to identify differences in students' engagement in school life, in terms of both socio-personal characteristics (sex and educational stage) and type of school (state, private with some state funding and cooperative). Participants were 1229 students aged between 9 and 17 (598 from a worker cooperative and 631 from state and private stated-funded schools of the Basque Country and Catalonia). Three components were distinguished in engagement (emotional, behavioural and cognitive) as measured by a Spanish version of the Leadership, Organisational Learning and Student Outcomes (LOLSO) questionnaire by Mulford, Silins and Leithwood (2004). These data are related to the responses given to the Psychological Sense of School Membership (PSSM) questionnaire by Goodenow (1993), which examines factors affecting school engagement, with specific focus on students' sense of belonging. The results indicate that girls' engagement is higher than that of boys; that it decreases as students move up the school; and is higher in the worker cooperative than in the state or private stated-funded schools. Engagement was also found to be related to teachers' work and the relationship between teachers and students. © UPV/EHU.