Impulsivity and self-control are often inversely related, yet little is known regarding their concurrent role in gambling disorder (GD). Therefore, we aimed to explore self-control and impulsivity with respect to GD severity, gender, and age in an adult sample with GD. The secondary aim of this study was to consider the roles of these factors by means of path analysis. One hundred and twelve adults who met criteria for GD completed the Barratt Impulsiveness Scale (BIS-11) and the Self-Control Scale (SCS). Structural equation modeling (SEM) evaluated direct and indirect effects of impulsivity and self-control on GD severity. Impulsivity and self-control were negatively correlated. The SEM identified a direct positive relationship between impulsivity and GD severity. Impulsivity also mediated a relationship between age and GD severity. High impulsivity levels are associated with greater severity of GD. Future studies should examine treatments targeting impulsivity and self-control in individuals with GD.