Face preferences and facial attractiveness influence broad and varied aspects of social behavior, including partner choices, hiring decisions, and voting behavior. Past research has identified several visual parameters that influence the attractiveness of faces. This chapter outlines prominent theories of attraction: the perceptual bias account (which proposes that attractiveness judgments are a functionless by-product of the visual recognition system) and the evolutionary advantage account (which proposes that attractiveness judgments are psychological adaptations that identify high quality potential mates). Next, this chapter summarizes the literature surrounding the relationship between expression, self-resemblance, apparent health, youthfulness, averageness, symmetry, and sexual dimorphism (i.e., masculinity and femininity) and perceived attractiveness. In line with the evolutionary advantage view, the literature supports the proposal that facial attractiveness is a potentially adaptive indicator of mate quality in men and women. This chapter concludes with discussion on the relevance of this work to transgender and gender diverse people seeking gender-affirming surgeries and emphasizes the need for additional research using gender and sexual minority participants.