Gathering information via question asking is an essential and effective tool for learning. However, it also requires learners to select from a near infinite space of possible queries. Here, we investigate a potentially powerful guide for question asking in young learners: the relationship between cause and effect. Children (5- and 7-year-olds) read a storybook about an event with an unknown cause and made several choices between two questions to ask about possible candidate causes. Both questions revealed similar information, but only one had the potential to determine whether a candidate was capable of causing the event described. Participants overwhelmingly selected causally relevant over irrelevant questions, with strong performance in both age-groups and for all types of information. These results suggest that young learners employ their prior knowledge of the causal connections between events to identify relevant queries during information search.