Adults have a vertical attention bias (VAB) that directs their focus toward object tops and scene bottoms. This is consistent with focusing attention on the informative aspects and affordances of the environment, and generally favoring a downward gaze. The smaller size of children, combined with their relatively limited interactions with objects and scenes, could lead them to have diminished bias that only gradually develops. Alternatively, an early coupling of attention to action space could lead to VAB similar to adults. The current study investigates the developmental timeline of VAB, comparing 4-7-year-olds to adults. Participants (N = 50 children, 53 adults; 58% White, 22% Asian, 6% Black, 2% Native American, and 12% other) observed naturalistic photographic triptychs (48 objects, 52 scenes, all online). They made similarity judgments comparing a test figure to two flanking figures containing either the same top or same bottom. We found that (a) children and adults exhibit a common VAB for object tops and scene bottoms and (b) the adult bias is stronger than children's. Exploratory analyses revealed the same age trend within children, with VAB increasing with age, and asymptoting at the adult level at age 8. This demonstrates that despite age and body size differences that could make the environment for young children relatively disparate from adults, their perceptual system is already largely attuned to their individual interactive action space, with only minor continuing residual development. The findings support that, like adults, young children focus their attention on their action space and body level affordances, where they interact more with tops of objects and bottoms of scenes.