Cues indicating environmental threat have been shown to influence women’s preferences for physical traits in men. For example, women’s beliefs about their vulnerability to aggression are associated with a stronger preference for physical formidability and aggressive dominance in male bodies and faces. In the current study, we extend these previous findings by testing whether dangerous world beliefs predict accuracy in processing facial cues associated with affiliation or deception. In addition, we include a sample of men to determine if these effects generalize to both genders. In the present study, participants viewed a series of images of a target displaying both Duchenne (genuine) and non-Duchenne (posed) smiles and were asked to categorize them as real or fake; participants also completed the Belief in a Dangerous World scale. Results revealed that for women, greater dangerous world beliefs predicted greater accuracy in discriminating real and fake smiles; no relationship was observed between dangerous world beliefs and smile detection accuracy for men. These findings uniquely demonstrate that dangerous world beliefs predict greater accuracy in adaptive face perception; however, this relationship seems to be specific to women.