Online role-playing video games provide opportunities to connect socially and can enhance self-esteem. For some players, however, overuse fosters dependency leading to negative psychosocial and health consequences. Per the American Psychiatric Association, criteria for diagnosis of Internet gaming disorder (IGD) follow an addiction model, and include characteristics such as preoccupation, tolerance, and withdrawal. Though useful, this approach lacks a focus on underlying motivations that may partially explain vulnerability to IGD. This study explored relationships among IGD symptoms and two potential risk factors: social phobia and player-avatar identification. Participants (N = 394; 50% female) were recruited from game-related internet forums and surveyed online. We tested a model in which a positive relationship between social phobia and IGD symptoms was partially mediated by stronger avatar identification. Social phobia, avatar identification, and IGD symptoms were strongly positively related, and we found modest support for mediation as proposed. Accordingly, we suggest that fundamental needs for social connection and approval are potent motivators to play, particularly for socially phobic players uncomfortable with face-to-face contact. Vicarious interactions through a gaming avatar may fulfill these needs, reinforcing stronger self-identification with the avatar, which in turn can offer players a stronger and more positive sense of self. Such influences may work synergistically to motivate increasing intensity of and preoccupation with gameplay, contributing to IGD. These results support the use of player-avatar identification in assessing risk for IGD, developing treatment options, and reaching a better understanding of how socialization and identity can be influenced by virtual interactions and accomplishments. (C) 2017 Elsevier Ltd. All rights reserved.