Firearm-related violence is the leading cause of death for adolescents and can have lifelong ramifications, including to one's mental health and well-being. Through a scoping review of existing literature published since 1980, the current study describes nuanced pathways through which exposure to firearm violence (direct or indirect) can contribute to the development and exacerbation of posttraumatic symptomatology during adolescence (ages 10-19). Furthermore, this review explores moderators and mediators of this relationship, shedding light on the interplay between individual, familial, and societal factors. Findings from the reviewed studies (N = 16) demonstrate various links between direct and indirect firearm exposure and short- and long-term posttraumatic symptomatology in adolescents and point to necessary solutions that encompass consistent firearm violence prevention and mental health support. Results can inform future research, policy development, and intervention strategies to mitigate the adverse psychological effects of firearm violence on the vulnerable adolescent population.