Purpose – Online environments, such as social networks and online forums, offer new possibilities and a wide variety of identity and social relationship management for the users. However, besides functional contributions like mutual support and easy ways of establishing contacts there are critical perspectives on computer-mediated communication (CMC) regarding detrimental behavior like provoking, overbearing, attacking and insulting other users, especially when anonymity is high. Recent research has shown that these kinds of online behavior are associated with personality traits like sadism, machiavellianism, narcissism, and psychopathy (Buckels, Trapnell & Paulhus, 2014) and can lead to severe trouble, negative affect and dysfunction in online communities (Cheng, Danescu-Niculescu-Mitzil & Leskovec, 2015). As such, in the public perception “trolls“ have become a synonym for counterproductive and dysfunctional behavior (Bishop, 2014a, 2014b). Our research aim was to shed more light on trolling and counterproductive online behavior theoretically as well as empirically. In other words: We wanted to know who is behind the troll? How can he or she be characterized in terms of personality traits and what can be expected from trolls when it comes to the organizational context and job performance? Design/methodology/approach – In a first step, we formulated a theoretical framework on counterproductive online behavior. On that ground, two online surveys (N = 122; N = 133) were conducted. The first study’s goal was to develop and validate a questionnaire on counterproductive online behavior. The second study analyzed counterproductive online behavior and tested for possible interrelations to personality traits and work-related outcomes. Originality/value – Using explanatory factor analyses we developed a 40-item questionnaire with two higher dimensions: Constructiveness and destructiveness. 15 subscales focus on different communication styles and trolling strategies. The second study tested the two dimensions of counterproductive online behavior on work-related outcomes such as work engagement, task-related performance and interpersonal facilitation. As was expected, destructiveness revealed significant negative correlations with all work-related outcomes as well as deviant work behavior. Constructiveness, in contrast, showed positive associations with interpersonal facilitation. Practical implications – So far, research on trolling and counterproductive online behavior has been limited to theoretical or anecdotal approaches in most cases (cf. Bishop, 2013a, 2013b). Our study aimed at a more systematic examination of this CMCspecific phenomenon. However, our study design, acquisition of the samples and the formulation of the questionnaire suggest that the results are valid indeed. On that note, our research is a first step for a deeper understanding on people showing counterproductive online behavior.