Since the 1940s, social psychologists have conducted research testing whether it is possible to accurately identify members of perceptually ambiguous groups. This study quantitatively reviews the research on the perception of ambiguous groups to better understand the human capacity to accurately identify others based on very subtle nonverbal cues. Standard random-effects meta-analytic techniques were used to examine the distinctions between different target groups in terms of their identifiability, as well as to compare rates of accuracy across perceptual modalities (e.g., photographs, audio, video) and other study design differences. Overall, the accuracy of identifying targets was significantly better than chance guessing (i.e., 64.5%). Furthermore, stimulus modality was found to be a moderator of accuracy. Other moderators (e.g., time of exposure, analytic approach) were identified and examined. These data help to document and characterize broad trends in the proliferating and expanding study of the perception and categorization of ambiguous social groups.