<p>Stressors are prevalent throughout and following military careers and dispose military personnel and veterans to stress-related psychopathology. Most available interventions primarily focus on symptoms, overlooking the predisposing risk factor of stress, and are subject to access barriers. Digital interventions targeting stress can increase access and reduce the incidence of stress-related psychopathology. This systematic review evaluated available research on digital interventions targeting the impact of stress on stress-related mental health outcomes among military personnel and veterans. This systematic review is registered in PROSPERO (ID#masked) and funded by the U.S. Department of Veterans Affairs. Following PRISMA guidelines, three databases (APA PsycInfo, PubMed, PTSDPubs) were systematically searched until September 30, 2025. Inclusion criteria were: samples containing military personnel or veterans; quantitative measures of stress, depression, anxiety, trauma-related distress, or mood as primary measures; digital interventions targeting stress; and peer-reviewed research. Critical appraisal checklists were used to assess the risk of bias. Data were synthesized according to the Joanna Briggs Institute Manual for Systematic Reviews. Of the 15 studies that met inclusion criteria, 13 had acceptable data quality (at least 70% on critical appraisal checklists). Samples were predominantly White (100%), male (86.7%), and veteran-only (66.7%). Posttraumatic stress disorder was the most common type of mental health disorder characterizing samples (40%). Digital interventions were delivered in app (60%), web-based (33.3%), and task-based (6.7%) formats. Two studies examined only feasibility and acceptability of the interventions. Of the 13 studies that examined the clinical impact of digital interventions on stress-related mental health outcomes, only six reduced stress-related mental health outcomes compared to a control condition. Monitoring stress was the most common feature of digital interventions, followed by a variety of skills-based content (e.g., breathing techniques). Only two studies examined just-in-time interventions that prompted an intervention in response to stress detection. Digital interventions targeting stress among veterans and miliary personnel are limited in number, diverse in approach, and offer limited evidence for efficacy across stress-related mental health outcomes. Nevertheless, existing research provides a strong foundation for future stress intervention development, including just-in-time interventions, to facilitate a more adaptive response to stressors and increase resilience.</p>