Prereading questions can be an effective tool for directing students' learning. However, it is not always clear what the online effects of a set of prereading questions will be. In two experiments, this study investigated whether readers direct additional attention to and learn more from sentences that are potentially relevant to a set of prereading questions. Eye-tracking data indicated that participants directed additional attention (as indicated by first-pass reinspection and lookback duration) to sentences that were potentially relevant to the prereading questions they had received. Participants also learned more information from these sentences (as indicated by free recall rates). Judgment data suggested that the featural similarity (both lexical and semantic) of a sentence to a prereading question can be a strong indicator that a sentence will be deemed potentially relevant by readers. Results are discussed with respect to an account of instructional effects in which featural similarity drives early attentional allocation through memory-based processes. (Contains 4 tables and 1 footnote.)