Young preschoolers rapidly acquire new information from social partners but do not learn efficiently from people on video. We trained parents to use Whitehurst's "dialogic reading" questioning techniques while watching educational television with their children. Eighty-one parents coviewed storybook videos with their 3-year-old children in 1 of 4 conditions: dialogic questioning (pause, ask questions, and encourage children to tell parts of the story), directed attention (pause and comment but do not ask questions), dialogic actress (show the videos with dialogic questioning by an on-screen actress embedded in them), or no intervention (show the videos as usual). After 4 weeks, children in the dialogic questioning group scored higher than children in the directed attention and no-intervention groups on story comprehension and story vocabulary measures. Scores from the dialogic actress group fell in between. On a standardized measure of expressive vocabulary, children in the 2 parent-interaction groups exhibited significant improvement over their pretest scores. Results indicate that parent-led questioning enhances children's learning from video stories at age 3 and that a video incorporating an on-screen dialogic questioner may also be effective. Mechanisms behind the effect of dialogic reading-style interventions are discussed.