Objective: Little is known about people who have been exposed to a suicide attempt by someone they know. The purpose of this study was to examine how many people have been exposed to a suicide attempt by someone they knew and whether the exposure was associated with general well-being and suicidal ideation. Method: A population-based online survey was conducted during 2019 in Denmark (n = 6,191). The associations between exposures to suicide attempt and general well-being (WHO-5) and suicidal ideation (Suicidal Ideation Attributes Scale) were examined using linear regression analyses. Results: Overall, 24.6% reported having experienced a suicide attempt by someone they knew. Of those, 46.5% had experienced a suicide attempt of a close relation and this group reported having been more affected by the event. Those exposed scored lower on general well-being (b: −3.0; 95% CI: −4.2 to −1.8; p > 0.001) and higher on suicidal ideation (b: 1.6; 95% CI: 1.3 – 1.9; p = 0.001) than those not exposed. Half of the exposed reported not having received sufficient support after the event. Conclusion: Suicide attempt affects a substantial share of the population, and it might be relevant to ensure that support is available for those exposed perceived to be in need of support.