This study examined the effect of films with English subtitles, Persian subtitles, or no subtitles on the listening comprehension of English language learners in Iran. 90 intermediate English students were divided into three groups that viewed episodes of a documentary. One group viewed with English subtitles, one with Persian subtitles, and one with no subtitles. After each viewing, the students took a multiple choice test on listening comprehension. The group with English subtitles performed best, followed by the group with Persian subtitles, and the group with no subtitles performed the worst. The results suggest that English subtitles best support listening comprehension, while any subtitles are better than none for developing this skill.