Background: Both poor mental health and suicidality (MH/S) are significant concerns for the Veteran population. The proposed study will identity Veterans at greatest risk for poor longer-term MH/S based on their initial post-separation transition experiences, with the goal of informing interventions that can prevent poor longer-term outcomes. We will also examine the role of exposure to COVID-19 stressors in this relationship. Significance: Although there has been a call for additional attention to upstream predictors of Veterans' MH/S to better inform prevention and early intervention efforts, no study to our knowledge has examined the implications of Veterans' initial readjustment experiences for their longer-term MH/S. Yet, whether Veterans are able to secure meaningful work, meet their financial needs, experience health concerns, and have sufficient support as they adapt to civilian life may set the stage for how their lives unfold over time, either protecting them from or putting them at risk for poor longer-term outcomes. In addition, the initial transition timeframe represents an opportune time for interventions aimed at interrupting trajectories that lead to chronic readjustment challenges, and thus, warrants additional attention. Innovativeness and Impact: This study, which involves a ten-year follow-up assessment of Veterans who first reported on their experiences during the initial transition from service, will build on prior research in a number of ways. First, we are not aware of any study that has examined how Veterans' initial readjustment experiences are related to their longer-term MH/S to inform efforts to intervene with high-risk Veterans. Second, the study's focus on how predictors of Veterans' longer-term MH/S differ for women and men can inform the development of interventions that can meet women's unique readjustment needs. Finally, we are not aware of any study that has examined how Veterans' initial post-military readjustment influences their adaptation to subsequent life stressors, and in turn, their longer-term MH/S, offered another novel contribution. Specific Aims: Aim 1 is to identify Veterans at greatest risk for poor longer-term MH/S based on both their initial reintegration experiences, as well as changes in their readjustment during the transition period. Aim 2 is to identify sex differences in the impact of Veterans' initial readjustment experiences, as well as changes in their readjustment during the initial transition period, on Veterans' longer-term MH/S. Exploratory Aim 3 is to examine how Veterans' readjustment experiences influence their risk for and vulnerability to subsequent stress exposure (COVID stressors), and in turn, their longer-term MH/S. Methodology: Study aims will be achieved by re-surveying Veterans from the Veterans Metrics Initiative (TVMI) study (N = 7404), a population-based investigation of Veterans' health, vocation, finances, and social relationships during the first three years post-s...