We investigated pictorial versus contextual support effects over and above teaching of definitions on children's word learning and retention as well as the moderating role of reading comprehension. In a between-subject pre-post-retention test control group design, Dutch fourth graders learned concrete and abstract Dutch words. The context group received definitions and context sentences, the picture group received definitions and pictures, and the control group only received definitions. Children in the picture group outperformed children in the context group but not the control group on all words directly after learning. This learning gain, however, disappeared over time because participants in the context group retrieved the word meanings better than in the other groups 1 day later. Interestingly, reading comprehension moderated the forgetting effect, as low comprehenders in the experimental groups forgot less than those in the control group. Adding pictures to definitions, thus, leads to richer long-term knowledge for low comprehenders.