Though the left cheek appears more emotive, perceptions of attractiveness vary with gender. For the first time, this study assessed the relationship between perceptions of emotion (happiness) and attractiveness in naturalistic photographic portraits. One hundred ninety-two participants (63 male; 129 female) viewed pairs of left and right cheek poses, and made a forced-choice decision indicating which image appeared (a) more emotive and (b) more attractive (order counterbalanced). Half the images were mirror-reversed to control for perceptual biases. Results indicated a striking gender difference: for males, the left cheek appears both more emotive and more attractive; for females, preferences are subject to stronger perceptual influences, with the right cheek bias for emotion and attractiveness reversing to a left cheek bias when images are mirror-reversed. These findings suggest that if you want to show the world your "best side", men should lead with the left but for women, the right cheek is right.