International and national data continue to identify poor literacy standards among secondary school students. The researchers, in collaboration with a metropolitan secondary school in Perth, Western Australia, elected to use the Direct Instruction Reading Mastery program to improve students' reading skills. Data on reading performance was collected from 59 Year 7-9 students identified by their teachers as having poor reading skills. Students were assessed using the Woodcock Reading Mastery III and were retested twice during the remainder of the year. Teaching staff were observed delivering the program and were interviewed in the final term of the year to ascertain their experiences while using the program. Results showed a statistically significant improvement in students' reading performance. There was a moderate, statistically significant correlation between higher reading improvement and higher attendance. The program was effective for students regardless of equity group. Semi-structured interviews with the teacher and teaching assistants delivering the program indicated they were overwhelmingly positive about the program but identified difficulty delivering it with fidelity. This was also noted during classroom observation. The results from this research support the efficacy of using Direct Instruction programs, such as Reading Mastery, to improve the reading outcomes for adolescent students who are struggling to read. However, they also highlight the complexity of influencing reading success for students in secondary schools, with factors such as attendance and fidelity of delivery influencing the success of the program.