Several studies suggest that the increase in sexually transmitted infections (STIs) among men who have sex with men (MSM) could be due, in part, to human immunodeficiency virus (HIV) risk reduction strategies, which include engaging in oral sex over anal sex. The aims of this study were to evaluate oral sex behaviors and STI diagnoses and to investigate the potential dual role of oral sex as being protective for HIV, yet perpetuating STI transmission among MSM. We analyzed records from 871 MSM presenting to the Rhode Island STI Clinic between 2012 and 2015. We compared outcomes in men engaging in two HIV protective oral sex behaviors: (1) HIV/STI outcomes by men engaging only in oral sex versus those that did not, and (2) HIV/STI outcomes by men engaging in condomless oral sex with 100% condom use for all other sex acts versus those that did not. Men engaging in HIV protective oral sex behaviors were more likely to be HIV negative compared to men not engaging in them (99% vs. 93%, p < 0.01). In contrast, there was no significant difference in STI diagnoses between those that engaged in HIV protective oral sex behaviors and those that did not. The findings provide evidence to support the unique duality of oral sex: decreased risk for HIV and perpetuation of STI risk. Promotion of routine STI testing, including extragenital sites, is critical to address STI prevention among MSM. In the age of HIV prevention, addressing the ambiguous risks of discrete sex acts would be beneficial for both HIV and STI prevention education for MSM.