Serious games like PeaceMaker are emerging as a new medium for peace education (PE). We focus on the assessment of this computerized simulation of the Israeli-Palestinian conflict in order to identify the effects it might have in helping to narrow the knowledge gap between the players. In addition, we examine the role of news media use about the conflict in knowledge acquisition after playing the game. We conducted an experimental study with the participation of 185 Israeli undergraduate students of Jewish and Palestinian origin. In order to gauge the effect of the game with regard to knowledge acquisition about the conflict, we used a pre-and post-intervention experimental design and utilized questionnaires. We found that the knowledge gap between participants who held high levels of knowledge about the conflict and those who held low levels of knowledge about it before playing the game narrowed after playing it. Second, participants holding more knowledge about the conflict before playing the game were more likely to win it than those holding less knowledge. Finally, the game narrowed the knowledge gap between participants who consumed television (TV) as a major source of information about the conflict and those who did not consume it. Our results indicate that serious games like PeaceMaker are effective as a tool for PE, because they are useful in increasing knowledge about the Israeli-Palestinian conflict and narrowing the knowledge gap between the players, particularly for young people who are direct parties to this conflict and native to the online world.