In this study, the authors examine the impact of a yearlong supplemental reading course involving daily instruction in the learning strategies curriculum on lower achieving adolescent students' reading achievement and motivation. Using a multiple-cohort randomized treatment-control group design over 4 years, they compared achievement and motivation outcomes for 605 sixth-grade students who participated in the intervention with 530 students who did not participate and 593 ninth-grade students who participated in the intervention with 535 students who did not participate. Results indicated significant impacts of the intervention on reading achievement for ninth-grade students but not for sixth-grade students. Significant impacts on reading motivation were found for both sixth- and ninth-grade students. An exploratory follow-up study indicated potential benefits of a second year of intervention for sixth-grade students who are still low achieving after 1 year of intervention.