Eye movement data afford researchers valuable temporal information about exactly when in the reading record a given manipulated variable has an effect. One advantage of using eye movements is data are collected online during silent reading; therefore, they are uncontaminated by memory demands, articulation processes, or conscious strategies. In the present study, the eye movements are measured during Korean-speaking middle and high school students’ silent reading tasks. To investigate the word frequency effects, the study employs controlled sentence frames with embedded target words in an experimental design. Word frequency effects are interesting because they can demonstrate if less skilled readers’ mental lexicons are organized according to the same criteria as those of adults. For direct comparison, the participants read 36 experimental sentences using Koh et al.’s (2008) study that contains target words manipulated for high vs. low frequency. The word frequency effects are observed, with significant effects seen in single-fixation duration (cases where only a single fixation is made on a target) and total viewing time (all fixations on a target) eye movement measures. These results indicate that linguistic influences are primary in driving eye movements during reading for middle and high school students. This study suggests that further research should investigate the developmental trend in relationship to chronological age and reading ability. As the understanding of less skilled readers’ eye movement behavior while reading increases, measuring eye movements offers a promising approach to charting individual differences in reading.