Identification record PELANT, Josef. Griefing in Online Games. Prague, 2017. 86 p. Thesis (Mgr.). Charles University in Prague, Faculty of Arts, Institute of Information Studies and Librarianship, 2001. Thesis lead Vít Šisler. Abstract The goal of this thesis is to find out the frequency of griefing (harassment or intentional provocation of other players) among the players of the most popular genres of online games, and to determine the typical characteristics of griefers, based on following factors: age, gender, preferency of the game genres, and motivational factors of competition, socialization, and teamplay. The goal has been achieved through questionaire survey with the use of quantitative method. Among the most important findings belong that men are substantially more frequently griefers compared to women, griefers are more focused on competition than other respondents, approximately half of the surveyed players have commited griefing, and almost every player has been a victim of a griefer. It has also been found that griefers are more likely to identify themselves as victims of griefing, compared to the rest of players. Keywords griefing, griefer, game studies, online games, second life, world of warcraft