AbstractWorldwide, adolescents and young adults (aged 15–25 years) account for the highest proportion of new HIV infections, yet the uptake of HIV testing among this cohort is sub-optimal. Understanding factors that predict the uptake of HIV testing among adolescents and young adults is critical for designing effective and relevant interventions to increase testing. Drawing from the psychosocial constructs of the Health Belief Model, the study examined the effects of HIV risk perception, discussion of HIV with partners and knowing partners’ HIV status on HIV testing uptake among adolescents and young adults in two Nigerian universities. The study was conducted in 2018 and was cross-sectional in design, with a final sample of 784 male and female students selected using stratified random sampling. Adjusted and unadjusted logistic regression models were used to examine the effect of HIV risk perception, discussion of HIV with partners and knowing partners’ HIV status on HIV testing uptake. Only 50.6% of participants had ever tested for HIV with 30.7% being tested in the last year, with no significant differences by sex. After controlling for other covariates (age, sex and being sexually active), knowing partners’ HIV status, having discussed HIV with partners and being very concerned about contracting HIV were found to be significantly associated with ever being tested for HIV and recent HIV testing uptake. Uptake of HIV testing was found to be low in the study setting and fell short of the first ‘90%’ UNAIDS target. Age-appropriate strategies, targeting open communication on HIV/STIs and disclosure of sero-status between sexual partners are required to promote uptake of HIV testing among young adults and adolescents in Nigeria.