Limited research exists on how students qualitatively interact with high-stakes standardized assessments. Using a think aloud methodology, this study focused on investigating the challenges Reclassified Fluent English Proficient (RFEP) and English Learner (EL) high school students report while completing the critical reading section of the SAT, and the challenges the researcher observed. Another aim of the study was to investigate what types of reading, vocabulary, and testing strategies the students reported while taking the test and the strategies the researcher observed. The results yielded a higher percentage of reported challenges in the areas of reading and vocabulary, than observed challenges. For the strategies, there was a breakdown of observed and reported metacognitive and cognitive strategies for the areas of reading, vocabulary, and testing. There was a higher percentage of observed metacognitive strategies of underlining and rereading. In addition, reading strategies such as summarizing and analyzing were observed in this study, and a higher percentage of vocabulary and testing strategies were reported by the students during their think alouds. The study also examined the similarities and differences in challenges and strategies by student performance level on the critical reading test that was given to the students to complete. It was observed that the lower performance group experienced more reading challenges and the higher performance group reported more strategies overall. Considering that the vocabulary words in the reading passage played a big role in the challenges reported by the students, it can be said that the study has implications for the area of testing development, in that more appropriate reading passages should be created for RFEP and EL students. The study also has implications for educators in that they could implement a think aloud methodology in their English language arts curriculum and teach their students to be more metacognitive about their own challenges while reading. The results of this study suggest that the students who used a broader range of metacognitive strategies (including, reading, vocabulary, and testing strategies) had a better reading comprehension performance than the other students. Students can also learn what types of strategies to apply to try to overcome their challenges and comprehend the text they are reading.