Face emotion perception is important for social functioning and mental health. In addition to recognizing categories of face emotion, accurate emotion perception relies on the ability to detect subtle differences in emotion intensity. The primary aim of this study was to examine participants' ability to discriminate the intensity of facial emotions (emotion sensitivity: ES) in three psychometrically matched ES tasks (fear, anger, or happiness), to identify developmental changes in sensitivity to face emotion intensity across the lifespan. We predicted that increased age would be associated with lower anger and fear ES, with minimal differences in happiness ES. Participants were 9,546 responders to a Web-based ES study (age range = 10 to 85 years old). Results of segmented linear regression confirmed our hypotheses and revealed differential patterns of ES based on age, sex, and emotion category. Females showed enhanced sensitivity to anger and fear relative to males, but similar sensitivity to happiness. While sensitivity to all emotions increased during adolescence and early adulthood, sensitivity to anger showed the largest increase, potentially related to the importance of anger perception during adolescent development. We also observed age-related decreases in both anger and fear sensitivity in older adults, with little to no change in happiness sensitivity. Unlike previous studies, the effect observed here could not be explained by task-related confounds (e.g., ceiling effects for happiness recognition), lending strong support to observed differences in ES for happiness, anger, and fear across age. Implications for everyday functioning and the development of psychopathology across the lifespan are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).