The relationship between problematic gaming behavior and self-esteem is well-documented (King & Delfabbro, 2014). Moreover, the basic needs component of Self-Determination Theory has also been proposed as an organizing framework to understand gaming motivation (Lafreniere, Verner-Filion, & Vallerand, 2012; Ryan, Rigby, & Przybylski, 2006). Building on these ideas, the current study describes the development of a measure of contingent self-worth (Crocker, Luhtanen, Cooper, & Bouvrette, 2003; Crocker & Wolfe, 2001) specific to gaming experiences within Massively-Multiplayer Online Role Playing Games (MMORPGs), and explores the association between Gaming-Contingent Self-Worth (GCSW) and symptoms of Internet Gaming Disorder (IGD). A sample of MMORPG players was recruited through Amazon's Mechanical Turk (nź=ź600) to evaluate the reliability and validity of a GCSW scale. Exploratory and confirmatory factor analysis was used to identify a 29-item measure comprised of four components, including validation seeking, reward orientation, competition focus, and detachment. Additional analyses supported the hypothesis that GCSW is a strong predictor of IGD symptoms, beyond the contribution of motivation based on behavioral activities within the game. A measure of Gaming-Contingent Self-Worth (GCSW) is developed.Factors of GCSW include validation seeking, reward orientation, competition focus, and detachment.Associations between GCSW and Internet Gaming Disorder (IGD) are explored.GCSW predicts IGD beyond behavioral motives, weekly hours, and global self-esteem.