When navigating unfamiliar social environments, it is important to identify who is powerful. Determining who has power can be challenging because observers may have limited social information, and because people achieve influence for many reasons. In experiments with 3- to 5-year-old children (n = 192) and adults (n = 32), we investigated the developmental origins and conceptual structure of power judgments based on physical appearance. At 3 years of age, children already associated physical strength with expansive posture; soon after, expansive postures also supported judgments of normative authority and were joined by similar judgments about masculine facial structure. By the age of 4, children also matched high- and low-power versions of faces and postures together, indicating that they draw connections between different aspects of more or less powerful appearance. The complexity and timing of these changes highlights limitations in current accounts of the origins of adults' intuitions about powerful appearances. This study documents several novel developmental patterns that generate new hypotheses about the mechanisms that support the emergence of children's intuitions.