Despite the approval of PrEP for adolescents by the FDA in 2018, little is known about the awareness and attitudes about PrEP use among adolescent sexual minority males, who are at the greatest risk for HIV. We analyzed baseline data from the MyPEEPS Mobile study, a multi-site randomized controlled trial evaluating the effectiveness of a mobile behavioral HIV prevention intervention. A substantial proportion (68.2%) of study participants (ages 13–18) had previously heard about PrEP, and an overwhelming majority (90.8%) reported willingness to take PrEP, to prevent HIV. On the other hand, only about one third (34.6%) of participants indicated that taking a daily HIV pill would be “very” or “completely” effective in preventing HIV when having sex without a condom. These findings suggest that high awareness and willingness to use PrEP across various adolescent subgroups present opportunities for increased PrEP advocacy among this young age group.