The current study examined the effects of watching a closed-captioned movie clip on incidental vocabulary learning in a pre-test post-test experimental design. 120 college students from a college preparatory class, who were learning English as a foreign language (EFL), participated in the study. Two weeks before the treatment, all of the participants completed a 20-item vocabulary knowledge scale (VKS) that was adopted from Wesche and Paribakht (1996). One month after the treatment, they were given another VKS with 20 words. The participants were randomly assigned to one of the two groups: Group A (movie clip with captions); Group B (movie clip without captions). T-test analyses were conducted to examine development between and within each group. Results revealed that both groups demonstrated significant gains based on the VKS, and Group A improved more in the post-test. However, the development between the groups was not significant. Pedagogical implications of the study are discussed in the end.