When proficient middle school readers enter high school, it is generally expected that they can successfully comprehend high school text. If any literacy instruction is provided in high school, it is generally limited to students with a history of struggling with reading. Is it a reasonable expectation that successful middle school readers will be equally successful when dealing with high school text? If proficient middle school readers do encounter difficulties, what strategies might be helpful? What support might they need? Thinking aloud during the process of reading has been recommended as a strategy for improving comprehension (Harvey & Goudas, 2000; Wilhelm, 2002). Would such a strategy help proficient readers with a difficult reading assignment? Would thinking aloud have a positive impact on their ability to retell difficult text or answer questions about its content? The results of this study suggest that proficient middle school readers may not succeed equally in all high school texts, and thinking aloud is not equally facilitative to their success. (Contains 2 figures.)