The study examined how cognitive and motivational factors predicted reading skill and whether intrinsic reading motivation would explain significantly more variance in low ability readers' reading performance. One hundred and eleven children (aged 9-11) completed assessments of reading comprehension skill, verbal IQ, decoding skill and intrinsic reading motivation. Based on performance on the reading assessment, sixty-nine children were identified as high (n=32) or low (n=37) ability readers. Verbal IQ explained significant variance in high ability readers' reading comprehension, whilst poor readers' reading comprehension was explained by variance in their decoding skills and intrinsic motivation. In addition, intrinsic motivation explained significant variance in growth in reading comprehension skills in the low ability reading group, but not in the group of good readers. These results highlight the different factors restricting children's reading comprehension and the importance of intrinsic motivation as a contributor to low ability readers' performance in reading assessments.