This paper explores teachers' habits (1) in terms of setting homework for their students and (2) in terms of building on homework in the classroom. Based on data collected in UNESCO's Second Regional Comparative and Explanatory Study (SERCE), the sample size of this analysis is about 200,000 Primary Grade 3 and 6 students in 16 Latin American countries. SERCE applied standardised achievement tests and context questionnaires to these students, their families, teachers and principals of the schools involved. Choosing four aspects (student, classroom, school and country) for their multilevel study and focusing on two subjects (Mathematics and Language), the authors of this paper investigated the relationship between homework and students' academic achievement. The results of their analysis show that the majority of Latin American teachers set homework in all or almost all classes. Ninety per cent of the teachers estimated that it took their students between 15 and 30 minutes to complete their homework. Follow-up figures in terms of checking and correcting homework were somewhat lower, as was the number of teachers who actually built on homework in teaching sessions. This study highlights the importance of following up on the contents covered in homework in the classroom to maximise effective learning.