The aim of the current study was to investigate students' mind wandering while reading different types of textual narrations (macroscopic and submicroscopic) in chemistry. Another goal was to determine the relationship between mind wandering and students' reading comprehension. The participants were 65 female ninth grade students in Oman. Using a computer screen, participants were required to read about sodium chloride. A probe-catch procedure was used to measure students' mind wandering. Half of the slides presented textual narrations at the macroscopic level and the other half presented narrations at the submicroscopic level. We gave the students a paper and pencil reading comprehension test at the conclusion of the reading task. The findings indicated that participants' mind wandering while reading submicroscopic textual narrations was significantly higher when compared to reading macroscopic textual narrations. Also, there was a significant negative relationship between mind wandering and reading comprehension for both macroscopic and submicroscopic textual narrations. Implications and future research are discussed.