The current study examined perceptual differences between adults and youth in perceiving ambiguous facial expressions. We estimated individuals' internal representation for facial expressions and compared it between age groups (adolescents: N = 108, Mage = 13.04 years, 43.52% female; adults: N = 81, Mage = 31.54, 65.43% female). We found that adolescents' perceptual representation for facial emotion is broader than that of adults', such that adolescents experience more difficulty in identifying subtle configurational differences of facial expressions. At the neural level, perceptual uncertainty in face-selective regions (e.g., fusiform face area, occipital face area) were significantly higher for adolescents than for adults, suggesting that adolescents' brains more similarly represent lower intensity emotional faces than do adults'. Our results provide evidence for age-related differences concerning psychophysical differences in perceptual representation of emotional faces at the neural and behavioral level. (PsycINFO Database Record (c) 2019 APA, all rights reserved).