The naive belief that carried objects fall straight down when released has become known as the straight-down belief in the literature of intuitive physics. The present data show that, without formal instruction, many children revise the straight-down belief between 8 and 12 years of age. In Experiment 1, 6-, 8-, and 12-year-old children repeatedly tried to hit a target on the floor or on a table (without feedback) by dropping a ball while moving and judged the optimal release points. Whereas, in their judgments, the majority of the 6- and 8-year-old children exhibited the erroneous straight-down belief, most 12-year-olds gave correct forward answers. In their actions, children who held the straight-down belief dropped the ball significantly later than children who exhibited correct judgmental knowledge. The results of three additional experiments provide converging evidence for the claim that children use their naive beliefs to plan their actions. The data further suggest that the straight-down belief does not directly stem from a perceptual illusion. Age differences concerning the ability to execute action plans as intended are documented and discussed in relation to conceptual development.