The human face is a remarkable platform for conveying a variety of information, both biological and social. Studies have indicated that observers can infer human traits from faces. Facial structures serve as a cue for behavioral propensities linked to testosterone, e.g., aggression, physical strength, and threats. Predicting potential threats from face has critical and practical value for adaptation and survival; however, observer’s accuracy on judging behavioral tendencies remains questionable. The present review discusses the reliability of face structures to predict threats. We review how faces provide a cue to predict human tendencies, how facial-to-trait inference occurs, how facial structures can serve as a proxy for potential threats. Additionally, we discuss studies of how Eastern and Western culture may be related to judgments of aggression and physical strength. Based on our review, we propose other potential cues as proxies for threat propensities, socio-cultural contributions to threat perceptions, along with implications and methodologies for future research.