This chapter provides an overview of the literature on the sex differences in physical attractiveness, and how it influences mate choice. More specifically, it investigates evolutionary perspectives on men and women’s preferences for physical traits, such as ideal breast features in women, and masculine physical traits (i.e., muscularity, broad shoulders) in men. The chapter focuses on conditional (i.e., ecological/environmental) roles on mate preferences, in addition to examining possible individual differences, such as mate value. The chapter covers the following: (1) An overview of sex differences in attractiveness, including theoretical explanations, (2) A broad focus on women’s ideal preferences, (3) A broad focus on men’s ideal preferences, and (4) A discussion on conditional factors and individual differences influencing preferences for ideal traits.