Depressive disorders are strongly influenced by personality organization, attachment style, and defensive functioning. This study examined the associations between depression severity, defense mechanisms, and adult attachment styles, and explored potential moderating effects of gender. A community sample completed standardized measures assessing depressive symptoms, defense mechanisms (mature, neurotic, immature), and attachment dimensions (anxious, avoidant). Correlational and regression analyses indicated that higher depressive severity was negatively associated with denial and dissociation, while no significant links emerged for projection or mature defenses. Anxious attachment predicted greater use of projection (B = 4.65, p = 0.040), but depression did not moderate this association. Cluster analysis identified two distinct profiles: one with moderate depression and higher denial, and another with severe depression and markedly lower denial. Men reported higher dysfunctional defenses overall, whereas a significant depression × gender interaction suggested that depressive severity was associated with reduced dysfunctional defenses among women (B = −0.58, p = 0.002). These findings challenge prevailing evidence that depressive severity correlates with greater immature defense use, instead suggesting a possible defensive collapse at high symptom levels. The study contributes novel insights into how attachment and gender shape defensive functioning in depression, emphasizing the need for longitudinal and clinical replication.