Prior research on user behavior in online innovation contests has mainly focused on factors that positively impact prosocial, collaborative behavior, which should ultimately lead to innovative outcomes. However, little is known about the effects of more negative personal characteristics that might result in more competitive, antisocial, and even unethical behavior. This paper considers Machiavellianism as one of the traits that constitute the Òdark triad of personalityÓ and explores the relationship between Machiavellianism and participants' contribution behavior in online innovation contests. Specifically we investigate how Machiavellian characteristics influence individuals' contribution intensity, communication, and interaction behavior within the contest community as well as the quality and kind of their contributions. This study relies on multisource individual-level data from a large innovation contest in the field of public transportation. We find that the three dimensions of MachiavellianismÑdistrust of others, amorality, and desire for statusÑhave very distinct behavioral consequences in the context of online innovation contests. Specifically, the oppositional consequences of amoral manipulation and striving for status on the one hand and showing distrust of others on the other hand concerning contribution quantity and contribution quality are found. This study contributes to a deeper understanding of negative personality traits such as Machiavellianism as powerful predictors of behavior and of success within competitive innovation environments and leads to important managerial implications regarding the design and management of innovation contests. > >