This article reports the findings of a study investigating alexithymia, emotional instability, and vulnerability to stress proneness among individuals (N = 120) seeking help for hypersexual behavior. At the onset of treatment at an outpatient community clinic, subjects completed the Sexual Compulsivity Scale (SCS), the 20-item Toronto Alexithymia Scale (TAS-20), and the NEO Personality Inventory Revised (NEO-PI-R). The results of a hierarchical regression analysis revealed the best model in predicting severity of hypersexual behavior included the facets of depression and vulnerability to stress from the NEO and the Difficulty Identifying Feelings (DIF) factor of the TAS-20. Although the NEO domain of neuroticism appeared to capture the majority of variance in hypersexual behavior, the difficulty identifying feelings factor of the TAS-20 did make some modest, but significant, contribution to the severity of hypersexual behavior after controlling for depression and vulnerability to stress. These data provide evidence for the hypothesis that individuals who manifest symptoms of hypersexual behavior are more likely to experience deficits in affect regulation and negative affect (including alexithymia, depression, and vulnerability to stress). Possible reasons for these results are suggested and future recommendations for research are offered.