Recent literature has emphasized that individuals display varying levels of strategic reasoning. This paper presents ten years worth of experimental data from two countries exploring the existence and endogeneity o f gender differences in strategic sophistication. We report results from two experime ntal studies employing the beauty contest game, one from the classroom and one from the laboratory. We observe robust and signi…cant gender differences in strategic soph istication in favour of men in zero- stake situations. These differences disappear when a monetary prize is awarded. We also …find that depth of strategic reasoning varies with gender priming. Females display signi…cantly higher levels of strategic sop histication than males when gender is made salient. This effect of gender priming is driv en by females who believe women are superior in the game.