We examined mind wandering and memory for information in both live undergraduate lectures and a laboratory-based video lecture. In Study 1, which spanned a full-term live course, we found that degree of mind wandering did not increase over time in an average lecture, and was associated with poorer memory for lecture material. In Study 2, we examined changes in degree of mind wandering across three groups that differed in whether they viewed the lecture in video-recorded or live format, and whether or not they were enrolled in the course. We found that despite viewing the exact same lecture, participants who viewed it in video format showed a significant increase in mind wandering over the duration of the lecture, while those who viewed it live did not. This finding suggests that video, relative to live lectures are especially likely to elicit increases in mind wandering over the duration of a lecture.