This article reports the results of two experiments which compared the effects of reading-only, reading-while-listening, and reading with textual input enhancement (i.e. underlining) on Vietnamese English as a foreign language (EFL) learners’ learning of three aspects of vocabulary knowledge: form recognition, form recall, and meaning recall. Sixty Vietnamese EFL learners (32 beginner and 28 intermediate learners) were assigned to one of three experimental conditions: reading-only, reading-while-listening, or reading with textual input enhancement. During four weeks, all learners read four graded readers in their condition groups. Tests of target words were administered three times: one week before the reading (pretests), immediately after the reading (immediate posttests), and one week after the reading (delayed posttests). To gain more insights into the learners’ perspectives, follow-up semi-structured interviews were conducted. The results showed that the three reading modes resulted in word learning gains for the three word knowledge aspects tested. However, reading with textual input enhancement resulted in significantly more vocabulary learning than reading-only, while the reading-while-listening and reading-only groups did not differ significantly. In addition, form recognition had the largest gains while form recall the smallest.