Adolescent readers require a broad range of reading skills to deal with the challenges of reading complex text. Some researchers argue for a discipline-specific focus to address the low reading proficiency rates among secondary students. Disciplinary literacy attends to the different ways disciplines, such as science, generate and communicate knowledge. The purpose of this quasi-experimental study was to examine if and to what degree disciplinary literacy reading strategies impact student learning outcomes in reading comprehension and science content knowledge for 132 7th grade science students in five Southern Arizona charter schools and whether reading ability moderates that impact. The theoretical foundation for this study rested on expert-novice theory and Halliday's theory of critical moments of language development. It is not known if and to what degree disciplinary literacy reading strategies impact student learning outcomes in reading comprehension and science content knowledge for 7th grade science students and whether or not reading ability has a moderating effect on those student learning outcomes. The results for MANCOVA did not produce statistically significant results nor did the moderation analysis for the influence of reading ability on reading comprehension in the disciplinary literacy group. However, the moderation analysis for the influence of reading ability on science content knowledge resulted in conditional significant results for low (p < 0.01) and average readers (p < 0.05). Low to average readers in the disciplinary literacy group appeared to benefit the most from reading comprehension instruction focused on learning science content in the science classroom. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]