Gender differences in sexual attitudes and behaviors are typically believed to be large, yet recent evidence suggests that some gender differences in sexuality are much smaller than common knowledge would suggest. This article reviews gender differences in sexual attitudes and behaviors as reported by major meta-analyses and large datasets. In particular, this article reviews gender differences in heterosexual intercourse, masturbation, pornography use, attitudes toward premarital sex, and gender differences in same-gender sexuality. Evolutionary psychology, social cognitive learning theory, and social structural theory are explored as possible explanations for gender differences in sexuality.