This study explores the differences between more successful and less successful EFL readers in their comprehension performance and abilities to use reading strategies in interaction with English texts through thinking aloud while reading in pairs. Ten freshman high school students participated in pairs in four think-aloud reading tasks to think out loud for textual meaning and to answer reading comprehension questions about the texts they had read. The findings drawn from analysis of the reading scores and think-aloud protocols of the most successful pair and the least successful pair among the five pairs indicated that the most successful had scored higher on the comprehension questions and had performed think-aloud reading better than the least successful. Key differences characterizing the best pair from the weakest pair in this study were found to lie in readers' effective reading strategy use, sufficient linguistic knowledge and background knowledge, conscious monitoring of comprehension, and constant integration of textual meaning. Important implications of the results for pedagogical practices that encourage development of EFL reading skills are discussed.