This qualitative study examines a reading comprehension strategy use in English as a second language in upper-secondary schools one year after teachers participated in a professional development course. The data comprises observations, teacher narratives, and student interviews. A key finding is that the teachers used a repertoire of strategies from the course, suggesting an impact of the course. A second finding was a clear difference between how students in general and vocational programmes used the strategies taught: the vocational students used them in ways that indicated their relevance to them as learners, while the students in general programmes did not. The findings also suggest how and why students employ strategies. The article discusses implications for strategy instruction and how to enhance the reading proficiency of adolescent readers.