Background <p>Reliable epidemiological data about the prevalence, age-of-onset, and correlates of suicide-related outcomes are critical for effective suicide prevention. The present study aimed to investigate the lifetime and past 12-month prevalence of suicidal thoughts, plans, attempts. We then investigated whether these outcomes were associated with socio-demographic variables and mental disorders among first-year university students in New Zealand.</p> Methods <p>Data were collected between 2021 and 2023 through online self-report surveys as part of New Zealand’s contribution to the World Mental Health International College Surveys initiative. The final sample consisted of <i>n =</i> 3,702 first-year university students (overall response rate: 24.2%). Suicide-related outcomes were assessed using the Columbia-Suicide Severity Rating Scale (C-SSRS). Weighted prevalence estimates were calculated and data were analysed using multivariable statistical methods.</p> Results <p>Overall, 54.1% of respondents reported experiencing suicidal thoughts across their lifetime, with 29.6% having made a suicide plan, and 10.1% making at least one suicide attempt. Twelve-month prevalence of these outcomes was 37.4% (thoughts), 29.5% (plan), and 2.9% (attempt), respectively, and 12-month persistence among lifetime cases for these outcomes ranged from two-thirds for ideation to one-quarter for attempts. Non-heterosexual orientation and experiences of Major Depressive Disorder, Bipolar Disorder, or Post-Traumatic Stress Disorder were associated with greater likelihood of suicide-related outcomes.</p> Conclusions <p>Suicide-related outcomes are highly prevalent and persistent among first-year university students in New Zealand. Our findings demonstrate that specific demographic characteristics and experiences of mental disorder are associated with greater likelihood of suicide-related outcomes and highlight the need for effective initiatives to support first-year university students.</p>