Background: Effective notifiable disease surveillance depends on healthcare providers’ ability to identify and report cases. Evidence on factors associated with surveillance performance remains limited in high-risk regions such as Jazan, Saudi Arabia. Objective: This study examined factors associated with healthcare providers’ notification and case management skills, prevention and training competencies, and perceptions toward the Notifiable Disease Surveillance System (NDSS). Methods: A cross-sectional analytical study was conducted among 420 healthcare providers working in government hospitals and primary healthcare centers in Jazan. Data were collected using an adapted self-administered questionnaire. Composite scores were analyzed using t-tests, ANOVA, and linear regression. Results: Higher NDSS-related scores were associated with professional category, HESN+ training, epidemiology or surveillance training, and years of experience. In multivariable analyses, HESN+ training, formal epidemiology or surveillance training, professional category, and experience remained associated with notification and prevention-related outcomes. Notification and case management skills were also associated with more favorable NDSS perceptions. Conclusions: NDSS-related competencies and perceptions were associated mainly with training exposure, professional role, and experience. Strengthening HESN+ training and integrating surveillance education into workforce development programs may support disease reporting and surveillance capacity in Jazan.