Background Population-based data on risk factors for suicide attempts among veterans remains limited. Methods A national probability sample of 2307 veterans was followed over the course of four timepoints spanning seven years to examine how a range of baseline risk factors predict incident suicide attempt. Suicide attempt data were aggregated into a single follow-up timepoint. Results Sixty-two veterans (3.1%) reported attempting suicide during the 7-year period. The strongest risk factors for suicide attempts were higher baseline levels of loneliness, lower baseline levels of adaptive psychosocial traits (e.g., dispositional gratitude), baseline thoughts of self-harm, and greater post-baseline trauma exposures (12.3%–41.3% of explained variance). Veterans with multiple co-occurring risk factors were at greatest risk for attempts; of veterans with 0, 1, 2, 3, and all 4 of these factors, the predicted probability of suicide attempt was 2.0%, 5.3%, 13.5%, 30.4%, and 55.0%, respectively. Conclusions Baseline loneliness, dispositional gratitude, thoughts of self-harm, and new-onset traumas emerged as the strongest risk factors for suicide attempts among veterans, underscoring the potential importance of targeting these factors in prevention efforts. Veterans with multiple co-occurring risk factors have substantially greater risk for suicide attempts, suggesting that examination of multiple coinciding vulnerability factors may help improve suicide risk prediction models.