The typical finding of metacomprehension studies is that accuracy in monitoring one’s own level of understanding is quite poor. In the present experiments, monitoring accuracy was constrained by individual differences in both reading comprehension ability and working memory capacity (WMC), but rereading particularly benefited low-ability and low-WMC readers, effectively eliminating the relationship between monitoring accuracy and these reader characteristics. In addition, introducing a self-explanation reading strategy improved the accuracy of all the readers above mere rereading. The observed interaction between individual differences and rereading is interpreted in terms of concurrent-processing constraints involved in monitoring while text is processed, whereas the more general self-explanation effect is interpreted in terms of accessibility of valid, performance-predicting cues.