To investigate the format of mental images and the penetrability of mental imagery performance to top-down influences in the form of gravity information, children (4-, 6-, 8- and 10-year-olds) and adults (N = 112) performed mental rotation tasks. A linear increase in response time with rotation angle emerged at 6-years, suggesting that spatial properties are represented in children’s mental images. Moreover, 6-, 8-, and 10-year-olds, but not 4-year-olds or adults, took longer to respond to rotated stimuli pairs when gravity information was incongruent with the direction of rotation rather than congruent. Overall, findings suggest that in contrast to adults’, 6- to 10-year-olds’mental rotation performance was penetrated by top-down information. This research (a) provides insight into the format of young children’s mental images and (b) shows that children’s mental rotation performance is penetrable by top-down influences.