The relative reinforcing value of toys was assessed in the absence of, and immediately following, participant observation of a peer manipulating one of the materials toys. Preference assessments were used to identify preference hierarchies. Reinforcer assessments were conducted with the most high-preferred preference item, a low-preference the least preferred item, and a control. Each participant allocated responding toward the high-preference item during baseline. When reinforcer assessment sessions were preceded by a peer observation period, 3 of the 4 participants shifted allocation to the toy manipulated by the peer. The 4th participant only shifted allocation only when the high-preference stimulus was replaced with a medium-preference item stimulus. These data suggest that, among preschoolers, response allocation is influenced by observations of peers playing. (Contains 1 figure.)