To become proficient readers of Chinese, learners must identify characters quickly and accurately. Learners who are able to recognize characters rapidly are able to focus on the overall message rather than the meaning of individual characters. However, the complex orthography of Chinese makes decoding characters difficult. E-gloss tools such as Dim Sum have been highly touted as solutions to ease this burden for second language learners of Chinese (Shen & Tsai 2010; Xie & Tao 2009). Research has shown that when learners use these tools, reading speeds and comprehension scores improve; however, no research has investigated the effect of such tools on incidentally-learned vocabulary. This study compared incidental vocabulary gains by 19 students in two different Chinese courses, reading four texts with an e-gloss tool and four texts in a traditional paper format. Although a significant difference between the two reading formats was not found, simple comparisons of learning gains by individual learners in both reading formats suggest that students’ learning and reading styles may impact the effectiveness of reading with or without the e-gloss tool.