Objective <p>To examine the association between loneliness and mental health conditions (depression, anxiety, and stress) among university students and staff in Trinidad and Tobago (T&amp;T).</p> Methods <p>A cross-sectional, institution-based online survey was conducted between April 2024 and April 2025. Eligible participants who were drawn from the University of the West Indies, T &amp; T, completed validated questionnaires that included the DASS-21 for assessing depression, anxiety, and stress and the UCLA Loneliness Scale (Version 3). Multivariable ordinary least squares regressions were used to assess associations, controlling for sociodemographic characteristics. Subgroup analyses were conducted by age cohorts.</p> Results <p>Of the 423 eligible individuals invited, 372 completed the survey (response rate 87.9%). About 72.5% reported moderate to severe loneliness scores, and 76.2% experienced symptoms of at least one mental health condition. A one-unit increase in loneliness score was associated with a 0.31-point increase in depression score (<i>p</i> &lt; 0.01), a 0.18-point increase in anxiety score (<i>p</i> &lt; 0.01), and a 0.20-point increase in stress score (<i>p</i> &lt; 0.01). Associations were strongest in the 26–40 years age group. Participants who had a mixed-ethnicity background had significantly higher stress levels than Afro-Trinidadians (β = 1.12, <i>p</i> &lt; 0.05).</p> Conclusion <p>Loneliness was significantly associated with increased mental distress among university populations in Trinidad and Tobago. Findings provide post-pandemic evidence from the Caribbean supporting the need for institutional strategies that promote social connectedness and culturally responsive mental health support</p>