Healthcare personnel must deal with two problems of growing importance: violence in the workplace and the loss of work ability due to the aging of the workforce. Our objective was to evaluate, with a two-wave perspective design, the relationships of work ability, social support, and occupational stress with workplace violence in nurses. In an Italian public health company, we asked nurses to self-assess their work ability using the Work Ability Index (WAI) and we analyzed the relationship between this indicator and the violence experienced in the previous and following years. A total of 321 out of 344 nurses (99.3%) participated. In a logistic regression model, the WAI score was a significant protective factor for violence experienced in the previous year (OR = 0.94 CI95% = 0.90; 0.98 p < 0.01) and in the following year (OR = 0.88 CI95% = 0.84; 0.92 p < 0.01). In a hierarchical logistic regression model, social support acted as a protective factor (OR = 0.87 CI95% = 0.79; 0.95 for violence experienced in the previous year), while occupational stress was a significant determinant of the risk of aggression (OR = 3.65 CI95% = 1.90; 7.03 in the previous year, OR = 3.54 CI95% = 1.801; 6.947 in the following year). The difficulties that nurses encounter in carrying out their growing work demands in an environment that is not promptly adapted to their changing physical and mental states can lead to an increased risk of violence. Prevention of workplace violence should include organizational and ergonomic measures that reduce stress and increase staff support and work ability.