Gender differences in overall tobacco use clearly exist. In general, men are more likely to use tobacco products than are women. However, this simple generalization, ignoring type of tobacco products, time, and culture, masks many more interesting gender differences in tobacco use. There are pronounced gender differences in tobacco use of specific tobacco products within some cultures but not others. Yet these differences have changed across time, including narrowing and widening of this gender gap, depending on culture and tobacco product. This article addresses these issues and presents possible psychosocial, biological, and psychobiological explanations for these phenomena. In addition, the implications of these differences and ways to learn more about these important differences are discussed.