This study examines how three captioning types (i.e., on-screen text in the same language as the video) can assist L2 learners in the incidental acquisition of target vocabulary words and in the comprehension of L2 video. A sample of 133 Flemish undergraduate students watched three French clips twice. The control group (n = 32) watched the clips without captioning; the second group (n = 30) watched fully captioned clips; the third group (n = 34) watched keyword captioned clips; and the fourth group (n = 37) watched fully captioned clips with highlighted keywords. Prior to the learning session, participants completed a vocabulary size test. During the learning session, they completed three comprehension tests; four vocabulary tests measuring (a) form recognition, (b) meaning recognition, (c) meaning recall, and (d) clip association, which assessed whether participants associated words with the corresponding clip; and a final questionnaire. Our findings reveal that the captioning groups scored equally well on form recognition and clip association and significantly outperformed the control group. Only the keyword captioning and full captioning with highlighted keywords groups outperformed the control group on meaning recognition. Captioning did not affect comprehension nor meaning recall. Participants' vocabulary size correlated significantly with their comprehension scores as well as with their vocabulary test scores.