Autistic people are at increased risk of suicide behaviors (SB), including suicidal ideation and suicide attempts, and have higher rates of suicide death compared to non-autistic people (use of ‘autistic’ reflects community language preferences). Yet there is limited understanding of the mutable factors related to risk of SB for the autistic population. Beyond biological and behavioral traits, research with the general public reveals multiple social determinants of health (e.g., community-level resources, health policies) contribute to risk of SB. However, the impact of individual, community, and policy factors on risk of SB in the autistic population is unknown. Meaningful improvements in policy and practice will require an understanding of (1) how risk of SB clusters for autistic individuals across interdependent individual, community, and policy factors and (2) the current state of mental health service (MHS) provision among autistic people. To contribute to the long-term goal of reducing risk of SB for the autistic population, this project uses a sequential, mixed methods design, in collaboration with an established team of autistic stakeholders and policy and practice experts, to analyze multilevel, socioecological factors associated with risk of SB and receipt of MHS and to generate community-supported recommendations for suicide prevention. Aim 1 will identify clusters of socioecological factors (at individual, community, and policy levels) associated with risk of SB among two national samples of autistic youth and adults. Autistic people (aged 12-64) will be identified in two national healthcare claims databases (MarketScan private, CMS Medicaid) and integrated with public use and proprietary databases to create multilevel, longitudinal datasets containing individual, community, and policy factors. Data reduction, hierarchical clustering, and multilevel analytic techniques will partition individuals into homogeneous groups based on shared characteristics to identify underlying factors associated with risk of SB among autistic people. Next, using the databases developed in Aim 1, Aim 2 will evaluate socioecological factors associated with MHS receipt (psychotherapy, pharmacology, both, neither), dose (visits/year), and delivery modality (face-to-face, telemental health, both) for autistic people with documented SB and/or co- occurring mental health conditions. Informed by critical findings from Aims 1 and 2, through collaboration with autistic stakeholders and focus groups with additional autistic adults, family caregivers, and MHS clinicians, Aim 3 will establish community-supported recommendations to reduce risk of SB and facilitate receipt of MHS. In response to RFA PAR-23-095 and aligned with the NIMH strategic plan, this project will optimize real-world data collection systems to characterize clusters of multilevel risk factors of SB and factors associated with receipt of MHS among autistic people. Study results will produce translata...