||This study investigated the effects of competition in games and of exposure to a model on the aggressive and the high-active, but nonaggressive, behavior of 135 first- and second-grade boys. One group of subject-pairs observed an aggressive model, a second group observed a nonaggressive, high-active model, while a third group did not witness a model. Subsequently, one third of the boys experienced success in competitive games, one third experienced failure, and one third engaged in noncompetitive play. All subjects were than individually observed in a free play situation for the incidence of both aggressive and high-active, nonaggressive behavior. As predicted, competition in the games enhanced the class of modeled behavior, regardless of whether that class was aggressive or high-active in nature. Regarding both total aggressive and total high-active behavior: (1) in the absence of a model, the effects of competition were not significant and (2) in the absence of competition, the effects of the model were not significant. Therefore, it was apparent that it was the joint effect of the competition and the model conition that facilitated the class of modeled response. Contrary to prediction, success and failure were equally effective in enhancing modeled behavior. The relative ordering of the effects of success, failure and no competition was found to be consistent within subjects' grade level, but differed across grades.