Suicide as a global health challenge has recently increased among university students, while studies focusing on developing countries are inadequate. The purpose of this study is to examine the mediating role of the adversity quotient in the relationship between thwarted psychological needs (belongingness, social-environmental control, and meaningful existence) and suicidal ideation. This cross-sectional survey used simple randomization where a sample of 501 students was taken at the University of Ibadan, Nigeria (mean age = 16.58 ± 30.7 years). A questionnaire pack containing the Columbia-Suicide Severity Rating Scale (C-SSRS), Primary Needs Questionnaire (PNQ), and Adversity Quotient Scale (AQS) was used for data collection. The results showed a negative correlation between age, AQ, and suicidal ideation. However, the three dimensions of thwarted psychological needs were positively associated with suicidal ideation. The mediational model showed that AQ mediated the relationships between thwarted belongingness, social environment control, meaningful existence, and suicidal ideation. This study concluded that there is a correlation between age, AQ, and suicidal ideation, while the dimension of thwarted psychological needs is positively associated with suicide. Also, the adversity quotient, directly and indirectly, mediated the relationship between thwarted psychological needs and suicidal ideation. Recommendations and limitations are discussed.