Despite young children's increasing access to electronic books (e-books) and the evidence indicating their effectiveness for promoting language and literacy, no study has yet explored the e-book's effect in this area among students with intellectual disability (ID). Motivated by this challenge, the current study sought to investigate the effect of an educational e-book on vocabulary acquisition among students with ID. The effect on vocabulary of five repeated readings of an e-book among students with ID was measured and compared with that of children with learning disability (LD). The findings indicate that whereas two independent rereadings with the e-book were enough to promote vocabulary acquisition among the students with LD, at least five rereadings were required to make a difference in the group with ID. Explanations and implications of the findings are discussed.