This study examined sex differences in reading skill and reading motivation, investigating whether these differences could be better accounted for by sex, or by gender identity. One hundred and eighty-two primary school children (98 males) aged 8–11 completed a reading comprehension assessment, reading motivation questionnaire and a gender role questionnaire. While there were no sex differences in reading skill or extrinsic reading motivation, girls had significantly higher intrinsic reading motivation. However, responses to intrinsic motivation were better explained by gender identity than sex. In addition, a feminine identity was more closely associated with many different aspects of reading motivation than a masculine identity. Implications for our understanding of sex differences in reading are discussed.