We examined the prevalence and correlates of HIV testing among Iranian young adults. Demographic and behavioral data were collected cross-sectionally. A convenience sample of 19- to 29-year-old young adults (N = 3,246) were recruited from 13 major provinces. Generalized estimating equations models were constructed to identify the correlates of HIV testing. Only 13.6% (n = 443) of the participants had ever tested for HIV. In the multivariable analysis, male sex, married marital status, having extramarital sex, knowing a person living with HIV or who had died of HIV-related diseases, older age, higher education, and higher HIV-related knowledge were positively and significantly associated with HIV testing. Our finding that only about 1 in 7 Iranian young adults had ever tested for HIV was alarming. Interventions aimed at increasing HIV-related knowledge, HIV testing promotion, and identifying the barriers to HIV testing among Iranian young adults remain a public health priority.