This article completes a series of 3 studies on the lateral preferences of Brazilians of different age ranges. In previous reports, we assessed the lateral preferences of adults ranging in age from 20 to 72 years (Brito, Brito, Paumgartten,&Lins, 1989) and 4- to 7-year-old schoolchildren (Brito, Lins, Paumgartten,&Brito, 1992). In this study, we evaluated the lateral preferences of 625 children with ages ranging from 8 to 15 years with different measures of handedness derived from the Edinburgh Inventory (Oldfield, 1971). We found significant age and sex effects which depended on the measure of handedness. Factor analysis of the inventory revealed a single factor. Comparison of the data with those reported previously confirmed a sex effect on the distribution of handedness categories. Additionally, we found that the distribution of handedness categories in 4- to 7-year-old children and 8- to 15-year-old children differs from that found in adults, and removal of inventory items with reduced factorial validity (opening a box for both samples of children and broom for adults) accentuates these differences. Children are more mixed-handed and less right-handed. Item analyses of the data indicated that these differences are only partially dependent on the degree of novelty of the tasks included in the inventory. The implications of these life span age trends in laterality for current hypotheses involving experience-induced neural plasticity in interaction with environmental factors are discussed.