Studies of lexical coverage are valuable because they reveal the importance of vocabulary knowledge to comprehension. Lexical profiling research is also extremely useful because it indicates the vocabulary knowledge necessary to understand different text types such as novels, newspapers, academic lectures, television programs, and movies. Moreover, lexical profiling research provides teachers and learners with concrete vocabulary learning targets that students can seek to achieve and evaluate their knowledge against. However, there are only three studies that have precisely investigated the effects of lexical coverage on reading comprehension (Hu & Nation, 2000; Laufer, 1989; Schmitt et al., 2011), two that have directly investigated its effects on listening comprehension (Bonk, 2000; Van Zeeland & Schmitt, 2013), and one that has done this for viewing comprehension (Durbahn et al., 2020). With few studies and few variables that may affect comprehension examined, discussions of the generalizability of lexical coverage findings are likely overstated. The aim of this article is to clarify earlier research findings and highlight areas where further research is needed.