Objective: This study assessed the prevalence of sexually transmitted infections (STIs) and associated risk behaviours among undergraduate students at the University of Benin, Benin City, Edo State. Materials and Methods: A cross-sectional study was conducted among 385 undergraduate students of the University of Benin. Data were collected using a structured questionnaire and analysed using SPSS version 24. Descriptive statistics were presented using frequencies, proportions, and mean scores. Multiple logistic regression analysis was used to identify independent predictors of sexually transmitted infections. Statistical significance was set at p < 0.05 at a 95% confidence interval. Results: Approximately 18.2% of respondents tested positive for at least one STI. Staphylococcus infection (35.7%) was the most frequently reported infection, followed by gonorrhoea (30.0%), syphilis (20.0%), and chlamydia (14.3%). Factors significantly associated with increased likelihood of STI occurrence included being single (AOR=1.46, p=0.027), younger age (AOR=1.73, p=0.015), previous STI diagnosis (AOR=2.06, p=0.001), poor knowledge of STIs (AOR=1.73, p=0.008), inconsistent or incorrect condom use (AOR=2.01, p=0.002), social norms discouraging sexual health discussions (AOR=1.65, p=0.017), peer pressure influencing risky sexual behaviour (AOR=1.49, p=0.023), and limited access to health services (AOR=1.82, p=0.005). Conclusion: STIs remain prevalent among undergraduate students in this study, with Staphylococcus infection, gonorrhoea, syphilis, and chlamydia being commonly reported. Strengthening sexual health education, improving access to reproductive health services, and promoting safer sexual practices among undergraduates are recommended.