Abstract: Introduction: Housing instability is a significant issue among Veterans, with age-related variations in risk factors and outcomes. This study examines whether participation in Veterans Health Administration (VHA) Homeless Programs reduces suicide mortality among Veterans experiencing housing instability, and variation across age groups. Methods: This study analyzed a nationwide cohort of 662,682 Veterans with indicators of housing instability between 2014-2019. Logistic regressions estimated suicide mortality risk, stratified across five age categories (18-34, 35-44, 45-54, 55-64, 65 + years), controlling for demographic, military service, and health-related variables. Results: Suicide mortality rates were highest among Veterans <34 years (131 per 100,000 person-years) and lowest among those aged 55-64 and 65 + years (62 per 100,000 person-years and 70 per 100,000 person-years, respectively). Across all age groups, suicide mortality risk factors included White race, low or no service-connected disability compensation, and recent suicide ideation or attempts. Although Veterans aged 65 + were least likely to use VHA Homeless Programs, those who engaged with these services were 40% less likely to die by suicide, an effect only seen in this age group. Conclusions: Tailoring age-specific housing interventions to address Veterans' unique needs across the lifespan may significantly reduce suicide mortality risk among this population.