This study assessed the extent to which captions, textually unenhanced and enhanced, can draw learners' attention to and promote the acquisition of a second language (L2) grammatical construction. A pretest-posttest-delayed posttest experimental design was employed. Seventy-two Korean learners of English were randomly assigned to an enhanced captions group, an unenhanced captions group, and a no captions group. Each group completed a series of treatment tasks, during which they watched news clips under their respective captioning condition. The target L2 construction was the use of the present perfect versus the past simple in reporting news. For the enhanced captions group, the present perfect and past simple forms were typographically enhanced using a different color. Eye-movement indices were obtained to examine attentional allocation during the treatment, and oral and written productive tests and a fill-in-the-blank test were used to assess participants' gains. A series of mixed-effects models found both captioning and textual enhancement effective in drawing learners' attention to and facilitating development in the use of the target construction. In addition, positive links were identified between attention to captions and learners' gains.